View Full Version : Transmission Temp
denverdale
06-24-2002, 07:16
I took another drive this weekend to get past the 500 mile mark. I also experienced my second fill up. Mileage was great. Got 20.15 mpg with mostly highway mountain driving and about 90 miles of in town stop and go. I noticed that the transmission temp guage indicated about 200 to 210 degrees as I was driving in town. That seems high to me, but thought I would ask the forum. If I had my trailer behind be (8500#), it surely would be much higher. What is normal?
By the way, I rreally understand why everyone enjoys driving their Dmax's now. It is a lot of fun.
Denverdale
gardnerteam
06-24-2002, 07:35
200 to 210 seems a bit high for the Allison. Mine in a 2002 runs about 160 hwy & town in 90 to 100 degree heat in Mexico and Guatemala, and ran up to 200 to 210 working it hard off road in 4WD in the same heat(my truck weighs 8900 with nothing in the bed). Towing 10,000 lbs in 70 to 80 degree heat over the Cascades produced 200 on the uphill and 160 on the downhill. While 200 to 210 is not overheating by any means, from all the trucks I've seen and read about that is abnormally high for D/A normal driving, even in town. In my last 6.5 Peninsular CC 4X4 truck, pulling 18,000 lbs on long grades, my beefed 4L80E would go to 275 degrees, which I think is too hot, but the 4L80E normally ran at 200 to 210 degrees until I put a large exterior cooler in the custom from bumper, then it dropped to 160 with a high of 220 while towing. I built in a large exterior cooler in the custom front winch bumper (Ruenel type) on the D/A, but haven't hooked it up because the Allison runs so cool.
pullinpower
06-24-2002, 07:47
denverdale, I too see 200 to 210 deg.unloaded while driving in town,on the interstate it usually goes to 195 deg.This is on a 01, I thought it was because the front bumper didn't allow enough airflow. This is not "hot" but thought if I put my gooseneck with my backhoe on it it would get "hot".Guess I need to go hook up to it and see :D
Topic moved to 2500HD/3500 HD Trucks & Drivetrain forum.
I have a 2001 HD, D/A and have seen 200 degrees towing 9,000 lbs. The only time it hit 210 degrees was in 90 degree outside temp and the AC on, in the city. I think the AC makes it run 10 or 15 degrees hoter than normal. The temp never went over 200 towing heavy loads or on a hill. The fan also kicks in around 200 degrees trans temp. The engine stays the same at 190 to 200 all the time.
denverdale,
I too think this is unusually high. I am down here in the Springs and my tranny is usually running about 175 to 185 degrees, about two lines below the 200 deg. mark. In fact with this hot weather, I expected it to go up a little but I have never seen it go over 200 deg.
Great to see another newbie from Colorado! I have talked to a few other guys in town with Duramaxes and asked if they knew about TDP, but they just look at me like...huh :rolleyes:
Is this is a great forum or what!
Don
Vette Racer
06-24-2002, 09:11
denverdale,
Towed 23,180 lbs total combined weight in 96 degree weather at 70-75 MPH. Trans ran 190-200 and engine was 200 all the time. Hills didn't matter, fan just turned on and temps remained the same. 9.0 MPG on the pedal, cruise worthless! Truck completely stock. I thought the Dmax wasn't doing too good until I weighed the mess and found out I had a lot more weight on than I thought. What a truck! Next tow will be with the "Juice"! Can't wait!!!
Black Dog
06-24-2002, 10:21
The fluid temp on the Allison will go higher in unloaded stop and go driving than it will when towing a heavy load on the freeway. The more stops and starts you have, the higher it will get. 200 - 210 is nothing to worry about.
denverdale & others,
I've posted this topic several times & have been working with my dealer for many months regarding this same issue. It does give me some piece of mind to know however, that my truck is not the only one with what I think is a HOT tranny. In the past no one else claimed these hot temps but me.
I took it in a couple of weeks ago showing 215 on the dash gauge. The service mgr. hooked up the tech 2 and read 213. The gauge is right on. It only reaches the high temps when driving around in town. Mine has gone all the way up to 230-240 showing on the gauge almost to the red-line. Dealer called GM tech assis. & enginneering. They were told the tranny temp should be within 10 degrees of the engine temp. My engine temp has never gone over 195 even while towing or 4wd. SOMETHING IS WRONG!
Fix: Dont't know if you could call this a fix but it did help. My dealer was impressed. The Bow Tie blocks at least 50% direct air flow to the little tranny cooler. Why mount a cooler directly behind a fixed airflow obstruction??? I fabricated a curved deflector baffle that wedges in the slot in the middle of the cooler bracket (on top) and curves up wedging in the trough on the front plastic grille. It's the full width of the cooler. No holes to drill.
Tranny temps now run 15-20 degrees cooler & have yet to go over 200 even with 100 degree air temps & high humidity. My concern is will the temp now come up in winter months.
ON EDIT: Just read Black Dog's post. I really hope your right. Someone posted before when I was asking for help that temps over 200 would decrease tranny life by some 30-40%. I went through the search but can't seem to find it.
Billy
[ 06-24-2002: Message edited by: Billy14 ]</p>
billy14,
San Antonio barely gets below 40 deg F in the winter, why even worry about it. If it is really a concern just pull your deflector out. BTW, what did you use for the deflector? Sheetmetal, plastic, old coffee can??? :D
Don
CSDMAX
I know, I know, & it makes me sick. I like cold weather. Used to live in Denver for 6 yrs. Back when it was 40 deg. in January it took forever to get the tranny temp up to 150. Just don't want to have to take it out & put it back again. It may be 85 one day & 40 the next down here. Know what I mean?
As for the deflector, I used 18 ga. galvanized sheet metal & hit it with black spray on bed liner. Gives it a textured appearance & you can't tell it's there. Blended in real nice. I have a small metal brake which made it easy to form the angles needed to lock it in place on the cooler bracket & grill.
If you want to risk posting your Email address, I could do a cad drawing, save it as a bitmap, & send it to you.
Billy
Also have seen transmission temps around 210 with in town and slower driving. I read somewhere that the tow/haul mode allows for the transmission to lockup more or in the lower gears? Tried that and found that temps were in the 170 range!! This past weekend I towed a 10000# trailer in normal mode as I had been doing. Transmission temps got up to 200 in slower speed driving conditions in the mountains. Switched to tow/haul and the temps dropped 30F for the same kind of driving!! Also I noted in the GM manual that they say to put the transmission in neutral if sitting in traffic for 5 minutes or more to avoid overheating transmission. With today;s traffic that may be a problem more and more.
Also have seen transmission temps around 210 with in town and slower driving. I read somewhere that the tow/haul mode allows for the transmission to lockup more or in the lower gears? Tried that and found that temps were in the 170 range!! This past weekend I towed a 10000# trailer in normal mode as I had been doing. Transmission temps got up to 200 in slower speed driving conditions in the mountains. Switched to tow/haul and the temps dropped 30F for the same kind of driving!! Also I noted in the GM manual that they say to put the transmission in neutral if sitting in traffic for 5 minutes or more to avoid overheating transmission. With today;s traffic that may be a problem more and more.
I just towed to Parker, CO, and back. Weighed about 20,000. Ran speed limit (75) all the time. Ambient temps varied from 70's to mid 90's. Trans temp and engine temp remained within 10 degrees of one another - 200 most of the time.
Looking under the hood the other day, I noticed that the trans cooler lines went into the passenger side radiator tank, then to the cooler. That would tend to keep the temps similar. (I'll re-check that routing). The ducting is a really great idea. Although 200 degrees doesn't bother me, I was thinking of a deicated fan for the cooler.
Jake99Z71
06-24-2002, 17:22
My 2001 has always run within 10 degrees of the engine. I have seen 210 degrees in the city when the outside temperature is 90+ degrees. My engine is usually running 210 degrees. I have shot it with a Raytek temperature gun to confirm temperatures with the gauges in the truck. I have also switched to the Deep pan and 100% Amsoil ATF to help with these hot tranny temperatures. I think with having the engine running a little hotter than normal it bleeds heat into the tranny more. A good fix would be to disconnect the connection to the radiator. One of my coworkers suggested putting in a 3way ball valve and shut offs to reroute around the radiator.
DMAXDiva
06-24-2002, 17:41
Hey Billy14:
Would you mind passing on your deflector drawing to me too? I've been concerned about potential airflow restriction/overheating issues ever since the new Ranch hand replacement was installed last month (especially now that summer is upon us...nothing like being stuck in Houston traffic in 100+ degree heat! :rolleyes: ).
Thanks!
[ 06-25-2002: Message edited by: DMAXDiva ]
[ 06-25-2002: Message edited by: DMAXDiva ]</p>
Billy14 ~ I too am interested in the drawing. ~ odoh
odoh1@hotmail.com
billy14,
When you have completed the drawing, you can send it to me. Thanks! :D
Don
[ 06-25-2002: Message edited by: CSDMAX ]</p>
pullinpower
06-24-2002, 18:43
billy14, I too would like to see your air deflector.
[ 06-25-2002: Message edited by: pullinpower ]</p>
denverdale
06-24-2002, 19:04
Thanks everyone for the input. I think I will just watch the temp guage for now and see if it continues or if that was just something that happened because it is new. Did't notice the high temp this morning, but didn't drive that far either.
Denverdale
bhinrichs
06-24-2002, 20:00
I have a 2002 with 14,000 on it now. My trans temp seems to be a direct reflection of how hot it is outside.
In the winter it runs down around 150 - 165. It has continously been at 190 - 195 going down the interstate in these last few 95+ degree days.
I get up to the 210 degree range in town as well.
These are all unloaded temperatures. All at interstate speeds (except in town).
Bert
HELP :eek: :eek:
O.K. guys & girls. Please spare me a little time here. I'll have to pull my deflector out, take the measurements, & do the drawing. I promise I'll get to it as soon as I can. Pretty busy right now with my business.
I have your Email addresses as of 6/25 at 12:30 A.M. You may want to go back into your posts & delete these as per one of our administrators post regarding the scamming issue.
On Edit: Hmmmmmmm, I can see it now! Yes boys & girls you to can have your very own Ronco/Allison tranny cooler deflector for only $19.95 plus $50.00 shipping & handling. :D :D :D
Naw, I don't think they'd bite on that one. :(
Thanks,
Billy
By the way. Do I feel like a real dumb a$$. Practically took my whole dash apart including the A/C ducting looking for a real annoying rattle. Installed my Onstar module to get it working with the aftermarket stereo head unit a few days ago & just knew it had to be around the stereo. At least that's where it seemed to be coming from.
Well, I should practice what I preach. "Don't forget the obvious". Finally found it last night. My cologne bottle that I keep in the sunglass compartment in the roof console. Never rattled before. Oh Well!
[ 06-25-2002: Message edited by: Billy14 ]</p>
Billy14
I'd sure be interested as well...
*@aol.com
TIa
[ 07-23-2002: Message edited by: Mic ]</p>
denverale,
I now know what you are talking about. I headed south to Pueblo yesterday and it was hot (98 deg) and sure enough Alli hit 200 deg on the freeway. It stayed at that temp for the duration of the trip.
I have a call into one of the Allison service centers up in Denver to find out what they consider normal operating temperature for our climate and altitude.
billy14,
Thanks for the specs and drawings on your air diverter. Made mine up last night and installed it. Should make a difference for the tranny cooler without much impact on the radiator. Good job Billy! ;)
Don
A word of caution on temps. I was hauling a load of hay 2 nights ago. OAT was about 90, it was really windy, and I was loaded 7 layers high. It is an uphill climb, and because of the wind I was running in 4th. However, I was running level 3 on the Juice, with tow/haul out. Egt was 850, water temp was right on the mark, when all of a sudden, the trans temp overheat light came on. Sure enough, 1 needle width into the red. I went to tow/haul to lock the converter, slowed a bit, and as I had a long downhill, shifted to 3rd in hopes the fan would pull more air. Dropped out of the red immediately, and was back to 210 by the time I got home. Guess it is time for the deep pan install that I have been putting off. Interesting that there was so little heat rejection to the fan that it was just free wheeling.
Running at 200F around town unloaded sounds like trouble to me. Mine usually runs at about 140-170F unloaded (about 150F on the freeways) and only got it up to a shade over 200 on a hot day going up an 11% grade for about a mile towing my 10,000 fiver. Last October I did a cross country trip (Florida and back)towing the same fiver and never once saw anything approaching 200F. I would get a second or third opinion on safe operating temperatures for your own peace of mind. Maybe one of the Allison techs on the forum has an opinion on this.
Mine usually runs 1 or 2 ticks under 200, outside temps from 30s to over 105*F, loaded, unloaded doesn't seem to make much of a difference.
I went to the deep pan with Transynd a few months ago - used a total of 4.5 gal and flushed through the cooler line. So far I have not noticed any significant change in operating temps.
From the Allison Operator's Manual:
Operating Temps:
Sump - minimum continous 100* F
Sump - maximum continous 250* F
To Cooler - maximum intermittent 300* F
200* - 210* F should be within the operating specifications.
The manual is available as a download from:
http://www.allisontransmission.com
Choose the publications link from the top menu, and SEARCH BY PUBLICATION NUMBER -> OM3063EN . Lots of good info.
Listen up GMC owners,
The reason I designed the Allison cooler air deflector was:
1) I felt my tranny temp was too high (up to 234-240) with no load.
2) The CHEVY bowtie and chrome trim piece across the front of the grille blocks almost all direct airflow to the cooler.
Now the question. After reading through the posts on this thread & others regarding tranny temps, I have not noticed a GMC owner nameing high temps like us with the Chevy. I haven't been able to find a parked GMC to take a good look at the emblem yet. It may not block as much air to the cooler as the bowtie & trim strip on the Chevy. I think the grille on the GMC is all open with the exception of the emblem.
Let us know GMC owners but don't jump on the band wagon just yet. :D :D
Billy
Jake99Z71
06-29-2002, 16:20
Billy14,
I guess my post from above doesn't count as a GMC Sierra!!! I have seen my temps in the 200 degree range before changing to synthetic and after changing to the Deep pan. I now run about 170 degrees on the interstate and 200 degrees + in the city in stop and go traffic. I'm thinking it's time to buy an aftermarket cooler to put in line with a fan on it. I guess I will bag it in the winter around here. I have talked to my local dealer who knows nothing about Allison transmissions but yet they service medium duty Allisons.
Jake99Z71,
Oooooops redface.gif redface.gif
Didn't notice. Wonder how many others I missed? Well, guess we can discount that theory huh.
Billy
A GMC owner speaks. Ran the Dalton Highway today to the Arctic Circle. several steep (9 degrees)and long (2+ miles) grades. Tranny never went above about 175. I did notice one time in town, the tranny got hot (225) while puttering around a parking lot. My grill is covered with a lund screen front so there is some air flow restriction, although the deflector in the bumber seems to do a good job of forcing air to the cooler. No ideas as to why yours are running so hot. Even pulling, I don't reach those temps.
Billy....would appreciate a copy of your drawing...thanks Jim :cool:
Billy...thanks again for the drawings, they are excellent...does anyone know if the tranny cooler setup in a 2500 is the same as a 3500?
Jim
[ 06-30-2002: Message edited by: JEBar ]</p>
denverdale
06-30-2002, 09:58
Billy
I too would like a copy of your air deflector drawing. dalestephens@att.net.
I did a short tow last week and noticed that the tranny temp stayed below 200* as long as I was on the freeway. Once off the Interstate and on local streets, temp went up. I will tow up to the mountains over the 4th so after I get back, I'll post my observations. If the temps stay high, I'm going to see my dealer.
Great input on this thread.
Denverdale
Russ Denman
06-30-2002, 22:44
My GMC hits about 190 around town but normally stays at about 175 when towing. I use Tow/Haul when towing to which locks the TC. I do not use Tow/Haul when not towing which allows the TC to slip.
Those that are running hot may want to replace the Allison spin on filter. That apparently is recommend by Allison at 5K miles (I didn't see the post until I had 10K). You may not be getting enough flow through the filter.
Well we had the hottest day of the year here yesterday. My trans temp went up to 210 and stayed there. It normally always runs at 200 and stays there empty, does not matter if its on the freeway or in town. I've always thought this was to high but the trans tech at the dealer says thats the normal range for an Allison. I asked about putting an aux cooler on it, I was told that I would have to have special hoses made because of the fittings on the exsisting cooler. Also that there is no cooler in the aftermarket that has tubes large enough to allow for enough fluid flow.
Has anyone out there put on an aux cooler?
Hey boys and girls,
Just spoke with a service technician at an authorized Allison Distributor/Service Center up in Denver. Depending on what type of vehicle and usage, the Allison 1000 NORMAL oper. temp. range should be from 200 - 235 deg. MAX oper. temp is 285 deg. He said if your tranny is running 200-210 it is no problemo.... :D
Don
CSDMAX,
Thanks & it does make me feel better but, it still bothers me that the tranny would run tht much hotter than the engine. Never over 195.
Then again, I've never had a gauge on a tranny till now. What you don't know won't hurt you, right!
Billy
Myself today did some considerable driving in some 95 humid weather air conditioner full blast .... Noticed temp was two ticks off of 200, and at some times read 200 degrees......Never over, I was empty.... This is the first time I have seen it so high must be weather related, for sure.... Point is with the exception of Jake99Z71 ,MDRAG and I, everyone else isn't running synthetic and a deep pan, unless I missed someone ....... All though we are experiencing same temps??????? I thought for sure synthetic and additional capacity would keep it lower then stock setup and fluid......Although aware the synthetic will with stand heat longer, and still resist breakdown in substance, I thought it would not heat as fast and perhaps dissipate quicker...... Also with added capacity not get hot, so soon,exspecialy driving empty, and not towing ...... Within a matter of a few miles in the city it was steadily climbing and then with a jaunt down the interstate, seen no real drop in temp...... Hovered around the two ticks off of 200...... I feel the cooler is inadequate at best,air flow or size, this has to be the weak link ...... I did take a look at it behind the grill and WOW Billy your right bow tie and crossbar just about covers the whole dam thing ...... Gheesh ...... Do I see a change coming??????? If the aftermarket world sold a replacement grill with no emblem and cross bar I sure would be interested....... The existing ones only go over stock grill to further inflict poor cooling???????Prolong Heat sessions kills the life span of the auto tranny, Allison or not .......
MAC smile.gif
[ 07-03-2002: Message edited by: mackin ]</p>
ChevysRus
07-06-2002, 23:37
MY tranny rarely gets much over 150F. Water temp around 190-200 and tranny usually 100-150. Matter of fact today I finally dropped that short pan and replaced the spin on filter, pickup screen and installed the deep pan. Got a big tow coming up next week to Seattle with my car trailer and thought I would make sure it stayed cool. After finishing up and by the way the sucker took 12 qts to get the level up into the hot range. I had warmed it up to about 100F and checked the level and topped it off for total 12 qts.
Drained 9.5 qts, dropped the screen pickup and got another 1/2 qt. out and then the spin on filter gave up about another 1/4 to 1/2 qt.
Pulled the cooler line and drained/pumped 3 qts. out. So I had put in 12 qts. of TranSynd and pumped 3 out and had to put 3 back to get the level up there on the hot part of the stick. I think the cooler and lines and the tranny held about 1.5 qts. Some draining from the disconnected tranny line on the fitting side occurred as well.
Drove the truck about 80 miles after that and checked the fluid and right up to the hot range with probably about 1/2 qt. expansion left to overfull. Tranny temp right at 140-150F.
Anyway, I will let you know how hot it runs when I get back from my 2K round trip hauling the car trailer.
Meantime, I would suggest you should all check you fluid levels when HOT and if you are "in range" that's not good enough IMHO! In range can be up to 1-2 qts from full when HOT or in the upper hot band. To me an extra 1-2 qts. can lower the temp considerably. My truck has 18K and made several runs to Seattle towing and not towing. Never and I mean never has the tranny hit 200F empty or loaded or towing.
Has to be something simple like this or the spin on has not been changed as already suggested etc. Average outside temp for me in the summer is 90-100F. Winters we only get down to 40F and then the tranny takes forever to hit 100F.
So either I have the super tranny or maybe I am running more fluid by keeping it topped up all the way to the max (or just about 1/4-1/2 inch down from the top.
When you are looking at the dipstick, there is a range and then further up there is about a 1 inch "Full when HOT" cross hatch area. Maybe and it's just a maybe, you are running below this level. Take a peek and let us know.
Happy Cruising!
ChevysRus,
I will definetely take a look at your observations tomorrow regarding fluid level. I changed the spin on last week. Seems to shift a little smoother but the temp still pulled up to 205 with in town driving & my upper air deflector in place. Still 20 deg. lower than without it.
Felt the deflector on top was forcing air down & across the face of the cooler instead of through it so today (got bored) decided to fabricate one for the bottom thinking when the two air masses met they would be forced through the cooler.
WOW! Picked up another 15 - 25 deg. Anything over 30 mph tranny temp was around 170 - 175. Damn Bowtie! :rolleyes: Also lowered engine temp by 5 deg. (190 deg). Driving round & round the subdivision, lots of shifting & stop & go, still came up to 195 - 200 after 45 min. Got back on the road & it came right back down to 175.
One interesting note. THE FAN NEVER ENGAGED! Prior to the deflectors, it stayed on most of the time with temps up to 235 - 240.
Billy
Billy...any chance on getting a drawing of you latest creation? Am having an upper one made this coming week as per your specs. :cool:
HD Hauling
07-07-2002, 07:33
IT'S THE 2 TO 1 DOWN SHIFT PROGRAM THAT'S DOING IT.
HAD MY DEALER TECH CALL THE ENGINEER'S FROM GM AND THAT'S WHAT'S DOING IT.
ANOTHER SCREW UP FROM GM!!!
FIRST THEY TELL US THEY CAN"T UNLOCK THE T/C AND THE NEXT THING THEY DO IS UNLOCK IT.
AT LEAST THE GUYS THAT COMPLAINED ABOUT THE 2 TO 1 PROBLEM GOT IT TAKEN CARE OF!
NOW US THAT ARE PULLING BIG LOADS CAN WATCH THE TEMPERATURE GUAGE ALL THE TIME.
I'VE HAD IT WITH THIS SO CALLED HD TRUCK.A PERSON WONDERS NOW WHAT ELSE WILL GO WRONG NEXT.
ALSO THE TRUCK NOW SHIFTS AT THE LOST OF 2MPH INSTEAD OF 4MPH.
ONE THING LEADS TO ANOTHER.
WHAT DO YOU THINK GM COULD SCREW UP NEXT?
HAVE FUN WITH YOUR TOUGH HD FELLOWS!! :mad:
GM Smitty
07-07-2002, 07:58
I haven't looked that closely at the tranny cooler, but is it posssible to move it so it's not behind the bow tie? I recently installed a billet aluminum bow tie, and it seems as though it lets less air through than the plastic factory one. The 200 degree tranny temps bother me, I never had a problem in the cooler months (never went above 150), and now I'm seeing consistent 180-200 around town. And it's just around town, once on the highway, temp comes down. I'm sure the recent "juice" addition isn't helping matters though. What about placing an electric cooling fan in front of the tranny cooler with a manual switch inside the cab, that way, air is forced through it and not blocked by the damned bow tie. Some suggestions.
Josh
mark45678
07-07-2002, 08:45
a few weeks back billy14 posted he made a small air deflector to push the air up behind the grill emblem! In his post he though this was good for 20-30*f cooler! I think it was just a small piece of metal that he had bent a 45* angle in and mounted just under the cooler!
HD Hauling, Josh, Mark, & all others,
Lower deflector fits in just like the top one. No holes to drill & nothing to cut but I have to tell you, this one was a mother bear. Had to do a cutout to fit around the plastic bracket that screws onto the back of the bowtie. This bracket holds the grille in place to the cooler framework.
Keep in mind. These deflectors really bring the temp down & appear to work quite well when driving more than 20 - 30 mph. If I putt around with alot of shifts & slow speeds, the temp WILL eventually come up to almost 200 but not the 230 -240 I have reached before.
The BEST solution would be to lower the cooler itself down about 3 inches. This would allow direct airflow through the cooler without the need of the deflectors. I did this a few days ago & let the cooler just hang there with a tie wrap to keep it from bouncing around. Got the same results. This is what prompted me to do the lower deflector. Problem is I will have to design a new bracket to hold the center of the grille at the bowtie & new bracketry for the cooler itself. Another advantage to lowering
the cooler is it will be more in line with the fan blades where the strongest draw is. The center area of the fan provides little draw with the large clutch. Almost 10 inches. Guess where the tranny cooler is located. You got it. Right in the dead zone of the fan. Take a house fan & put your hand behind it. You'll feel very little draw in the center but directly behind the blades some will almost suck your hand to the cage. We have the same situation here with the coolers.
I will keep all posted. I don't intend to do drawings on the lower deflector yet because I still believe lowering the cooler itself will be the reall benefit.
Billy
ON EDIT: By the way, a shrouded fan such as we have Does help draw air through the diameter of the whole fan but, you will still not have the same flow & volume in the center as directly in front of the fan blades themselves.
[ 07-07-2002: Message edited by: Billy14 ]
[ 07-07-2002: Message edited by: Billy14 ]</p>
With this being said.....
Quote=>* Transmission oil cooler. This new transmission oil cooler, used with the Allison 1000 5-speed automatic transmission, is mounted below the radiator to preclude heat from the transmission going into the engine cooling system. It relies on RAM air from openings in the front bumper. The size of the cooler has been increased from previous models, and its larger 5/8-inch lines (compared to 3/8-inch lines previously used) provide for a very liberal 6-gallon-per-minute (GPM) transmission fluid flow rate. Transmission fluid cooling is substantially improved as a result.
===========================================
Where is the "GUTTER" man.....{RAM air from openings in the front bumper}
Those openings appears to be to low to be effective????Straight in flow not up? That big diversion plastic flapper in the middle behind the bumper, just keeps the air from going down? Should be pitched or curved to move more air up ........
MAC
:confused:
[ 07-07-2002: Message edited by: mackin ]</p>
mackin,
Where did you here this? Is this a change on the 2003's or from the 01's to 02's?
Below the radiator? Help! Mine is directly in the center & directly behind the bowtie BLOCKING all direct air flow which you yourself observed in one of your earlier posts. :confused:
I can lower it with the flex in the existing cooler lines. Can't go up with it (preferred) without changing out the lines. Don't want to go there!
Billy
Billy14,
That is the general's version for our "COOLER" from 2001 to present.......I'll HTML Link below......Believe me mine is smack dab behind the Bow Tie too........I would like to pitch the plastic diversion flap to direct more air .......I'll be on vacation soon and not traveling this year so I'll be looking into it when I get the chance.......Below radiator???? Got me.......
=>http://www.4x4review.com/news/new-silverado.asp
MAC
[ 07-07-2002: Message edited by: mackin ]</p>
bigbobed
07-07-2002, 13:53
The cooler is behind the GMC on my truck. There's an opening in the bumper that has a deflector behind it that forces the air up. I've never seen temps above 200 while towing in 90 degree heat. Usually stays around 150 around town.
Well, here we go. This may end up being the longest thread to date. On the other hand, myself & others maybe worrying about nothing. There have been numerous posts stating that 200 deg. with the Allison is right where it should be. I just don't understand why so many run 20 - 50 deg. cooler under the same circumstances. Tried the search again & still can't find the post where someone listed tranny life versus temps. Think it read that 200 would shorten the life by 30 - 40%.
6 gal. per minute through the LITTLE tranny cooler seems really fast. Not being a fluid engineer, I can't really answer this question with substance however, I do know for a fact that if the flow rate through a cooling device is too great given the volume of the device, the fluid will NOT remain in the cooler for a long enough time to reduce the fluid temperature sufficiently.
Example: In some situations (cars, trucks, etc.) removing the thermostat will allow the coolant to blow through the radiator. End result is the engine will sometimes run hotter than with the thermostat in place.
Maybe there is someone out there that really knows & can calculate flow rate given area of the cooler.
Billy
[ 07-07-2002: Message edited by: Billy14 ]</p>
denverdale
07-07-2002, 16:55
Billy
How about drawings for the new deflector?
Well, I towed my 8500# trailer and an additional 40 gals of water up in the mountains this weekend. While going up hill, the tranny ran about 221-215*. On fairly level highway and cool air, it still ran about 200*. I left the trailer up at the lot and was going to watch the temp coming home, but the darned thing is so much fun to drive that I forgot to monitor the temp guage.
I am not sure that I feel comfortable changing the pan and fluid right now. I don't have a mechanical limitation, just not sure I want to make those changes. I haven't had a chance to install Billy's deflector yet either.
Maintaining about 55 to 60 mph most all the way with the air on, I got 10.5 mpg on the way up. Haven't checked the mileage since I got back. Guage is still two notches above 3/4 so no need to fill up.
DenverDale
Billy ,
Here you go as it was me who posted......
=>Just thought I would share some info from the latest issue of The Turbo Register I received ....... One of many informative articles ......... This particular one was about magazines that did a study on tranny temps and what the approx. longevity would be ........ The results I'm reporting are from OFF-ROAD magazine, there were others testers(rags), but they seemed a little to extreme ..........
@ degrees = Life Expectancy
@175 = 240,000
@195 = 120,000
@220 = 50,000
@240 = 25,000
@260 = 15,000
@295 = 4,000
With these numbers I believe it would have to be consistently at these temps for, how often,how long????? I Couldn't say, for I'm just the messenger, not the expert......But the key is, like the article states, is a mear 20 degree rise cuts the life Expectancy in half.... :eek: So I hope to keep it COOL as possible........
These test I'm sure where done with Dino oil not synthetic and what will kill it quicker is temps and breakdown of oil, which will result in poor lubrication and eventual failure, over time ..... Also note the reason for the article was the need to install a tranny temp guage..... In a D**GE...... Take it for what it's worth......It does make sense all though......
MAC
[ 07-07-2002: Message edited by: mackin ]</p>
GMC
Must clean the bugs out of the tranny oil cooler.
Mixed driving and towing through what I call the mountains and Florida in 60F to 95F air temperature.
Combined towing weight approx. 17000 lb.
Air being pushed 72sq ft frontal area.
Engine water temp is always 195 to 200F.
Tranny temp, non towing always at 120 to 125F.
Tranny temp, towing in tow haule mode always 180 to 185F.
trailer L 34ft W 8ft H 9ft
GMC 2002 DURAMAX SLT EXCAB SHORT BOX 2500HD 4X4 AUTO
mackin,
Thanks, I should of known it was you with the tech data. smile.gif smile.gif
Kinda looks like a mere 20 degrees could save or add a bunch of miles to the tranny especially under load.
denverdale,
You must have missed my post. I've decided to work on lowering the cooler 3 inches to get direct ram air without a deflector. This would be our best bet. It would also put it closer to a direct draw off the fan blades. This may take awhile. Have to design & fab. all new bracketry for the cooler & a support for the front grille which would have to be removed. I'll let all know when progress is made.
Thanks again,
Billy
ChevysRus
07-07-2002, 22:33
I suppose there is absolutely no reason someone couldn't add a "SECOND" tranny cooler in line with the main cooler. Have to find one that has the same large flow rate or you could starve the tranny and build up too much pressure on the "To Cooler" side.
I suppose you could use the same original style cooler as the second cooler and just mount it lower into the airstream. Little bit of plumbing and you should end up with a real good cooling system. Add a valve to bypass the second cooler in the Winter. Just turn the valve on when the summer hot days start each year and you have an instant second tranny cooler.
Adding a small fan in front of the cooler sounds like a good idea as well, but the fan will restrict the airflow even more. But maybe easier than putting a second cooler in line.
I wonder if Allison uses a larger tranny cooler in the bigger trucks. If they do we could replace our puny cooler with a bigger one with the same flow rate, just an an extra QT or 2 of capacity.
But before you do all that just make sure your tranny is really full of fluid up to the hot mark when up to normal temp +/- 150F. That is the cheapest solution overall.
Good Luck
ChevysRus ,
Well, I guess I'll be carrying my camera with me to work for a while. When one of those "Allison Slush" boxes come in on one of those 18 wheelers, I'll get the guy (girl) to tip the hood and get some shots of the cooler...Good idea on the tranny fluid being up to snuff,I did that when I converted to deep pan -transynd..... Right to the top hot ,still two ticks off 200* to 200*,when the ambient temp 95ish and humid air conditioner on...... Just looking for ways to keep it cool..... I think the JUICE in my case, may ,perhaps (my foot) add to the equation.....
MAC ;)
[ 07-08-2002: Message edited by: mackin ]</p>
mackin,
It's not your foot. :D
Before the Juice was installed, I could creep around the neighborhood for 30 min. to an hr. & the temp kept rising to over 210. This is back when ambient air was still in the 70's - low 80's.
It's shifting & time that brings the temp up on mine.
Billy
I'm half tempted to take off the front grill for one day to see if the temps go down. Mine seems to hover around 200 degrees in 90-100 temps regardless of being on the highway or around town. During the winter it stays around 160.
Still wondering what will happen next year when we get our 5er :eek:
Don't want this thing to go into limp mode on Monarch Pass due to trans overheat!!
Bob
pullinpower
07-08-2002, 12:52
I saw on here somewhere where someone drilled the bowtie logo so it would pass more air,I have an extra laying on the shop bench(grabbed the one off my old grill when the replaced it ;) ) and was thinking I may drill some holes in it and try it out.
[ 07-08-2002: Message edited by: pullinpower ]</p>
The outside air temp today is a little over 100*, but my Allison temp is still 150 to 170. The water temp is 190*, but that doesn't change much no matter how hot it gets. For anyone, especially a tech, to say that 285* is ok for an Allison just doesn't know what he or she is talking about. The facts as Mackin presented them are well known and as far as I can see should be adhered to. Do whatever you have to do to drop those temps down to reasonable levels.
Billy14,
I just made a new lower air deflector and I can see why you are hesitant to make up some drawings. I modified the lower from your original drawings. I had to cut a rectangular hole to accomodate the center support below the bowtie and then had to notch below that on the bottom for the addtl support of the center support. Also had to trim (notch) the upper edges to avoid rubbing the inlet and outlet tubing. Now it's testing time to see if this adds to the cooling effect as you stated earlier. :D
denverdale,
I saw your post and it fits right into a little experiment I've been conducting.
I run between Cheyenne and Ft Collins daily, and working in engineering got me curious about my own vehicle. I have a 95 Yukon diesel and the tranny used to run close to 200 unloaded especially in traffic. I don't care who tells you, there is no reason to run trans oil the same as water temp unless you can cool the water down to 180 because that is the target if you want your tranny to live.
I've been involved with experiments on large transmissions and hydraulic systems with conventional oils and synthetics. As you move from 210 to 230 you are breaking down the additive package, 240F sulfur is coming out and by 250 and up your oil is reaching a point where it needs to be replaced. Don't buy into believing that synthetics are the cure all - they are good but give you less friction (less heat), but once they heat up they will be destroyed as well.
I worked for a company that designed very large equipment and coolers and places to mount coolers cost a lot. In the end, water to oil coolers were the most economical and that is what was installed. All the engineers knew what they would do if it was their own - add more cooling capacity! I've got the biggest plate mount cooler I can fit to my truck and it runs 170F in the pan on a 101F degree day doing 75 on I25.
I don't know how much improvement can be made to the new truck coolers but I believe there is always room for extra cooling. For the winter you avoid overcool by using a cooler thermostat.
I made a quick plastic air diverter for my cooler. It didn't help my trans still runs at 200 empty city or highway. The temps here are in the low to mid ninteys.
Billy14
If it`s not too much trouble I would like to have a drawing of your air deflecter. My email address is jgmg@gvtc.com It sounds like a good idea. Thank`s a bunch.
John G.
Billy14
If it`s not too much trouble I would like to have a drawing of your air deflecter. My email address is jgmg@gvtc.com It sounds like a good idea. Thank`s a bunch.
John G.
Yet another report.
Unloaded 85 degree weather, transmission is
around 160 degrees.
Unloaded 100 degree weather, transmission
is around 170 degrees.
Both of these with A/C on.
Loaded with 8K trailer, and truck bed full
with camping stuff as well as a dog, regardless of
up or down hill, temp around 185-190 degrees.
The only time I saw 200 was when I was carving through some mountain roads.
Bora
Bora,
LUCKY YOU! smile.gif smile.gif
Billy
But what is the difference?
My truck has only 3500 miles on it (yes I don't drive much).
Am I going to face similar temps as the truck ages?
Bora
Bora,
At this point, I would say no to higher temps with more miles.
It's a weird deal. We all basically have the same trucks. Some run hotter than others & there has not yet been any conclusive reasoning behind the different temp readings that I am aware of. Maybe its bad dash guages that have a reputation of not being highly accurate. Mine was checked with a Tech 2 & was right on. Others may not.
Also, there are those that should know that have posted 210 is fine & then there are those that say no way. :confused:
Billy
denverdale
07-15-2002, 19:49
Billy 14 & Bora
denverdale
07-15-2002, 19:53
Billy 14 and Bora
I am the one that started this thread. I only have 1400 miles on my truck so the temp better not go up as mileage goes up or I will be in hot water (no pun intended).
Denverdale
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