Allison vs. Heat - What fails?

[chuntag95]

As I fight to get my transmission temp under control, I find myself missing some info. The stats that 90% of all transmission failures are heat related are due to what? Is the problem the fluid breaks down or is it the clutch materials fail? If it's a fluid problem, then running the Transynd (PAO) Sythetic fluid will increase the fluids capability and not breakdown, problem solved. :cool: However, it the issue is the materials themselves in the transmission, then the better fluid will only help some and I need to continue along the lines I am going in keeping the temp down. :rolleyes:

Where are the Allison experts and what is the failure mechanism? :confused:

[dmaxalliTech]

Chris, you gettin carried away with this heat thingy arnt ya ;) Usually the convertor is first to fail due to heat, I have pulled many a converter from Hydromatics that is blue it has gotten so hot. Once it gets hot and comes apart, it pump the trans full of garbage. I think that if you could get more fluid to flow through the cooler then what is allowed you be better off. The pump creates an 'overage' of fluid. Overage is not pumped through cooler, just goes back to sump. I wouldnt be suprised if Allison is going to change that in the near future, thus lowering temps. I havent seen where Transynd helps lower temps much, but it has a better additive package and will allow for longer drain intervals. I dont know if they all have it but the last Alli I had apart had radial grooved clutches to help in fluid flow/cooling. What exactly are you running for temps? When? How?

[chuntag95]

Originally posted by dmaxalliTech:
Chris, you gettin carried away with this heat thingy arnt ya ;) What exactly are you running for temps? When? How? Eric,
I am afaid that is exactly what I am doing, getting carried away. I have always added transmission coolers as it seems the Texas summer just drains the life out of them and I have had more than one rebuilt or replaced in my life. :(

This truck has one and a gauge. :cool: But, on those killer days like when we hit 100*+ for 5 days in a row, the transmission is getting to 210* or a little more, driving in town, with no load. I added an 8" 800 CFM Fan to the cooler. It seems to work well and drive a larger delta to the inlet and outlet temps of the cooler. Without the fan running, the cooler seems to have the same inlet and outlet temps. :confused: I have 2 temp monitors with probes inbetween the fins on the in and out sides of the cooler, but they go out of range at 158* and I saw both out of range on Saturday. :eek: They read as little as 10 degrees lower than the transmission gauge and as much as 40 degrees. If you believe Mac's numbers

=>At degrees Life Expectancey conventional erl ....
175 240,000
195 120,000
220 50,000
240 25,000
260 15,000
295 4,000
then I am headed for trouble right after I am out of warranty. (I have the GM extended to 5yr/75K.) I do have Transynd in and I do change the spin on at every oil change. I want to keep the temps below 200 all the time and would prefer the 170-180 range. Am I expecting/wanting too much? :confused: Am I being a parnoid engineer worry wort? :rolleyes: redface.gif I love this truck and really will need to drive it a looonnnnggggg time, so I want to take care of it. I am a firm believer in PREVENTATIVE maintenance and if that involves a little redesign, so be it.
Chris

[chuntag95]

Eric,
A couple of questions. What is the flow rate of the Allison? How would I increase that flow per your recommendation?
Chris

[DalDMax]

Chris,
Have you gone to the Deep Pan yet?
Might help some to have a larger pool of fluid to pull from. Also the larger pan would radiate some heat away from the trans and fluid itself.

[chuntag95]

DalDmax,
Not yet. Not many have said the deep pan did a lot for them, but I think that theory is sound. I just have to decide where the best bang for my buck will be. I think a second cooler has a better chance of making an impact. The cost for a deep pan, filter and flush will be about the same as the extra cooler with a fan and thermal switch. Ulimately, I might do both and add gauges too. :D The question is, will I still be married and have the truck when I am done. :eek:

[ratlover]

:confused: I thought the temp/life expectancy chart was the expected life expectancy of the oil not the tranny. As long as you change the oil before it exceeds its usefull life you should be ok right :confused:

My plan is to run regular dex with a deep pan and change often. Plowing will give her a work out and I figure frequent changes and draining any crud outa there is best. I figure the frequent changes will keep the additive package up to snuff and get any small buggers out. The only advantage I see to synthetic is it lasting longer especially in high heat. syn is a bit to pricey to be dumping all the time and I think frequent changes are better and about the same cost wise as longer intervals and synthetic. JMO.....its probably not correct......

[Allison Jettester]

I just added a very large trans cooler made by Setrab of Sweden. My temps now stay at 160 - 170 degrees. The cooler looks like this:
http://www.derale.com/img/stackedplatecoolercore.jpg , only bigger. The stock cooler is a very lite aluminum cooler and not very big. It holds less than a pint of fluid where mine holds 3 pints and is made of copper.

[ 07-28-2003, 11:26 AM: Message edited by: Allison Jettester ]

[chuntag95]

Originally posted by Allison Jettester:
I just added a very large trans cooler made by Setrab of Sweden. My temps now stay at 160 - 170 degrees.
It holds less than a pint of fluid where mine holds 3 pints and is made of copper. Allison Jettester,
Where did you get the cooler? Where did you mount it? Did you put a fan on it? Is it temp controlled or bypassed? Please share your details.
Thanks,
Chris

[chuntag95]

Originally posted by ratlover:
:confused: I thought the temp/life expectancy chart was the expected life expectancy of the oil not the tranny. As long as you change the oil before it exceeds its usefull life you should be ok right :confused: I don't know, but if that is the case, I'm okay. Who has an answer to this question? Where are the guys that work for Allison?

[Silver Bullet]

For us non-engineering types...what are the benefits/drawbacks to copper vs. aluminum? :confused:

I like the idea of adding a bigger cooler and/or deep pan.

I ran from Dallas to Lubbock to Amarillo to Vernon...empty...this past weekend and never saw over 200 degrees. I picked up an empty 20' gooseneck stock trailer in Vernon and pulled it back to Dallas and I just barely saw the topside of 200. The outside temps ranged topped at 103! I ran 70-80 mph after I got the trailer...I ran slower to monitor EGT and boost...I ran with T/H engaged some...nothing appeared to change the tranny temp too much, but I was more concerned with my fan running...it ran a lot, but appeared to run less when I would slow down a little.

[77TransAm]

According to Allison's Tech Data book for the 1000/2000/2400 series transmissions, the typical continuous sump temp is 200

[Allison Jettester]

Chuntag,
I guess I'm like you, I didn't like the temps approaching 200 degrees after burning up several Turbo 400's due to towing.

Anyway, I put on the Setrab cooler for piece of mind. They are the no.1 most used coolers in the racing world and are used on the most expensive cars. I bought mine off ebay from a race car outfit, but I got lucky. You can get them here:
http://www.hbs-performance-offroad.com/products/Cooling/Setrab/

Mine is the # 640 on the list 11.25w x 12h x 2deep. I mounted it where the stock cooler goes. It comes with AN6 fittings. The stock cooler has 5/8 pipe fittings, so I got two AN6 females and welded 5/8 female pipe to them so I could keep the stock quick disconnect. I had to bring the lines down under the round cross member and bend them a little. They are some real tough metal so you need a really good bender. An easier solution would be to cut them and clamp hoses with the AN6 on the end.
I also had to remove the plastic scoop at the bottom of the radiator. I will probably fabricate something to replace it with.
I just noticed that the hbs-performance coolers have the Setrab metric connectors on them. You have to order the AN adapters.
Derale.com has Setrab coolers made to their specs with the AN fittings, but I don't see the big one I have. You might want to call them. Summitracing sells Derale products.

For those who think the trans might run too cool in the winter, I plan on putting an inline thermostat before winter - Summit part # DER-13011

I have pictures of the coolers side by side and a frontal view. I didn't take a picture of the bottom, but could tomorrow some time.

I have not towed with it yet, but am planning a trip up to Quebec next week and will let you know what the temps get to going up the mountains.

email me if you could like the pictures. bealejk@surfbest.net

Silver Bullet - Copper conducts heat much faster than aluminum.

Joe

[ 07-28-2003, 04:33 PM: Message edited by: Allison Jettester ]

[chuntag95]

Joe,
Thanks for the pictures. That is a really nice job! :cool: My concern is the connections. The welding to retain the QD will be a problem for me. I'll have to investigate that more as I want to keep the QD as well if possible. Why does the general not have standard fittings here? I was originally thinking of adding another cooler, not replacing the OEM, but looks like you have a cleaner solution. I can even move my fan over and only turn it on if I need it. Thanks for sharing your info and experience.
Chris

[Allison Jettester]

Thanks Chuntaq,
I found I was in error concerning the 5/8 national pipe thread on the end of the trans lines to the cooler. Apparently there is no such thing as 5/8 pipe (you learn something new every day :eek: ). Gm used 1/2 pipe thread fittings with a 5/8 id hole when they had the special quick disconnects manufactured. Also, concerning the connectors to the cooler, I recommend getting the connectors from the cooler provider as there are so many different fittings used. You can also find many providers on the web. Here's 2.

http://www.fittingsandadapters.com/
http://www.toolsforaircraft.com/conical/conical.html

Just make sure they are 5/8" to minimize pressure drop.

I would recommend to all to change the stock cooler as it is really chintzy -- small, 4 1/2" x 13", only has 8 stacked plates and is aluminum. I didn't like it the minute I saw it on the lot. Maybe the gauge is off and maybe 200

[ratlover]

So is the chart for life of the fluid or for life of the trany? :confused: :confused: :confused:

If one runs the tranny at a pretty much constant 220 and change the fluid every 50k should the tranny pretty much last for 300k easy?