is there FACT to back the 50mph-1st slam?

[MudNurI]

Okay folks, now I'm not second guessing any one here...But I gotta know..WHO said to drive 50mph, then slam the truck into 1st gear 3 times to reprogram the transmission? Where did this info come from. I still can't figure out what in the world it would change, I have reread the posts regarding it and just don't get it. If anyone can provide a link to some page explaining from Allison (or gm or whatever) why we should/would do this it would be great. I am very leary, as we are almost at 26,000 miles, which means in about 2 months, my transmission will be outta warranty, and don't want to do many 1st gear slams and then have something major give..at 36,001 miles.

thanks!
Brandy

[Silver Bullet]

I don't have anything to back it up, but I can tell you the Alli won't slam into first! It downshifts slowly...almost as if you would if you were downshifting a manual transmission. My curiosity got the best of me...I closed my eyes (OK...kept 1 eye half open for safety reasons!), gritted my teeth and threw it down!!! Nothing bad happened.

If you're gonna do it, do it before your warranty runs out!!! smile.gif

[mark45678]

OK now by putting into 1st at 50+ a few time in a row this puts the TCM (trans control modgel) into "fast learn" witch will relearn how much line presure it takes to hold without sliping after gear changes! by doing so your teaching your TCM not to defuel as long after shifts. NOW back to the part where you guys dont want to do this in fear of hurting your baby..... the truck is SO smart it will only down shift at the time when the next gear will not over rev the motor...... after a down shift it will go to 3300 rpm. for you guy that tow HEAVY you know on steep grades like 5+ % with 10k or more you may see almost 4000 rpm on grade breaking in tow\haul this will not hurt it! the factory is OK with this!!!!

[MudNurI]

I guess what I'm looking for is hard facts to back this up...not really the how it works type thing, but who said it works? I still don't "get it" as to why it would change anything in my transmission or why I would want to..if you guys are saying what it does is go back to "learn how I drive mode"..I drive the same way I did when I first got it..so what is there to relearn?

I'm still not buying this thing, sorry guys but my truck doesnt shift any different than it did 25,000 miles ago, well- okay for about 700 miles, I was in limp mode, but other than that, its been the same? someone has to be a skeptic I guess.

Brandy

[Ironhead]

When you guys do the 50mph to 1st, are you stepping on the brakes at the same time? or letting the engine do all the work of slowing you down. And do you need to come to a dead stop? Thanx...

[Idle_Chatter]

Brandy, from the Allison manual -

ELECTRONIC CONTROL SYSTEM
The 1000/2000/2400 Series electronic control system has the

[Idle_Chatter]

No brakes, Ironhead. Just run her up to 55 or so, let off the gas and move the selector lever to 1st and let it coast/shift down to nearly stopped. Then repeat a couple more times. Once you've convinced the TCM that you are crazy, or want to reset the adaptive learning data, it will go into "fast-learn" and start to restore all the shift information for the next few shifts. This "fresh" information will then be adaptively "averaged" over all the upcoming driving and thereby get "mushed" over time, which makes an occasional reset a good thing - unless you're like some of our members and *always* "Drive it like you Stole it" ;)

[bluenote]

I have done the 55mph to 1st gear a couple of times, and definitely did notice a difference the first time I did it, and not so much the second time. Maybe this question has been answered in a previous thread, but here it goes: Will I gain any benefit if I do this right before towing my 10K 5er after an entire winter with no towing (several thousand miles empty)?

[Turbo Al]

Idle_Chatter: It is NOT Turbo Al it's Big Al that's the Allison guru -- no offence (actually honored) but would just like to set the record straight.
When I first read the first post on this I was really sceptical but ---- did try it myself and can rest assured no damage done -- the Alision is even smarter that use bone heads and just smoothly shifts down the gears.
Turbo Non Allision Al

[Idle_Chatter]

Dang! Sorry Turbo-Al. I make that mistake all the time, even talking over the phone to Kennedy or face-to-face, like when we had the Wisconsin mini-rendezvous at Nel's place. In my mind, you're just the Allison guy instead of *BIG AL* Allison guy! BIG Allison Transmission! Big Al! Oh well, since I'm much too old a dog to learn any new tricks, you're just gonna have to move to the lower 48 and go to work for Allison! ;)

[Turbo Al]

Tom have Big Al send me a job application ;) .

[hoot]

"In order to optimize each type of shift for normal driving, shift controls must experience operation and shifting in a WIDE VARIETY of operating conditions. A

[Idle_Chatter]

It also works because by pulling the selector into 1st gear at that speed, you have literally "handed over" all transcontrol to the TCM to intercede and make the requested series of downshifts while protecting the trans. I'm sure that a 1st gear request at those internal speeds throws a "flag" in the control program and when it records a repeat series it knows that it's time to reset the adaptive learning and "go to school." The electronic manual is pretty informative (although *overloaded* with CYA warnings and liability based cautions about being in park, sudden vehicle motion, don't drop it on your foot, don't drink the fluid, etc. etc.) and talks about the grade braking upshifting to prevent overreving the engine. That answers a lot of questions about grade braking that people keep asking.

[Kennedy]

The last TCM update I did had some fast learn calibrations files listed in it. The details of this are unclear, but I would assume it may have quickened up the learn process.

[SledZep]

Plus, if you do it from 57mph 6 times in a row the information center lights up with...
"If you had bought a dodge you'd be walking now!"
:rolleyes: :rolleyes: :rolleyes: :rolleyes:

I did it and then raced around for the next 2 days in Tow/Haul pretending I had some juice.

[MaxDMax]

I pull a big 5er that puts me at 20,500 gross total and have a question. I have done this without my 5ver attach and see a positive difference unloaded. My need is to minmize the 5th to 4th gear down shifts. Should I do this with the 5ver attached? If so, should I drive it like I stole it following this if the 5er is attached? Any other hints on minimizing the downshifts on hills?

[ 05-19-2002: Message edited by: MaxDMax ]</p>

[motovet]

MaxDMax, How long have you been towing the trailer? Mine weighs about 10,000# and I had a lot of shifting for a while. It seemed way to sensitive, lots of downshifting under load, sometimes even to third when it was pulling good. Same goes for the grade braking, it would shift down way to quick and to often. Now with 7,000 mi., 2,500 of which towing, the shifting is much better. Downshifting under load is minimal and the grade braking seems right on the money. Yesterday I added the JUICE which will most undoubtably reduce the downshifting under load even more after my tranny figures out how to handle the new power. Good to see another motocrosser here.

[sonofagun]

MadDMax,

I do the downshift fix about once every 6 months. I wouldn't do it with a trailer attached. The downshifts are not dangerous but they are aggressive (at high rpm). Before I go on a trailer trip I do the downshift just before I hook up. The trans goes to fast learn and I get a rapid adjustment to the weight. Seems to work fine.

Good luck,
Bob

[NutNbutGMC]

^...This all sounds fine and fun, but I don't have the b@lls to slam mine into low gear from 55 mph. After all is said and done, none of 'em will run more than 97 MPH. Mini-vans will still smoke any Duramax. :mad: :mad:

[MaxDMax]

Thank you all for the info!
First one point I want to make the D-Max does better in my opinion than the Fords and Dodges I pass with much less weight, on about every trip but we always want more don't we!

motovet,
The trailer is a 37 foot toybox 5th wheel and weighs about 12,500lbs to 13,000lbs max loaded with 4 MX bikes, 2 pit bikes, 110 gallons of water, all our tools, race fuel, gen., air compressor and everything else. I just got the trailer about 3 months ago. have towed about it 3,000 miles so far. I also plan to get the JUICE, but am waiting on the 90hp box.

Bob,
I go on trailer trips almost every weekend, while I don't think it would hurt the D-max to do this before each trip, but I would have to do it every Friday on the way home. I drive the truck to work every day and just wonder if it re-learns being unloaded every week. Any thought or ideas on this?

NutNbutGMC
The 1st gear slam un-loaded is no big deal. I would estimate the strain on the transmission is not even 50% of what it goes through in a single fairly agressive downhill stopping situation from 50 to 0 on say at 6% downhill grade with a 12,000lb trailer. Just my thoughts.

Thanks again

[NutNbutGMC]

^.....MaxDMax, I'm working on it. Sure does seem like a drastic maneuver, however, I'll do anything to beat Mackin, from stop sign to stop sign.....

[ 05-20-2002: Message edited by: NutNbutGMC ]</p>

[OldCarKook]

NutnButGMC:
I can't beleive you said that!
"Minivans will still smoke a Duramax"

Did you buy your Duramax to go faster than 97? Because for the less than $10k, you can get yerself a brand spanky new Nip crotch rocket :cool: that will go 160mph right out of the box. And look at all the money you save. Plus, on two wheels you get to feel all the elements at 160. It's part of the experience. Like driving the DuraMax up to 97 and holding it there and then opening the window and sticking your head out for five minutes. :eek:

Seriously, why not drop that rear gear down if you really want speed.

I think the D-Max is AWESOME. ;) Plus, my days of driving faster than 75 on public highways ended a long time ago. You know, they are right when the say speed kills!

I share your concern about slamming it down a few gears at speed to "re-program". I think that will do more to reprogram MY brain than the Alison's brain!! :D

[sonofagun]

MaxD,

I don't tow heavy weight very often so my truck has learned to pull its own weight and not much more. If you pull regularly you are getting the benefit of that weight being factored in to your overall trans learning program. For those who are concerned about this it does no harm. Try it once, you'll see. What it does, apparently, is put the trans into fast learn (i.e. relearn) mode. It will learn anyway as you drive it, it's just slower. If you've changed your method of driving or towing you can wait for a while and it will learn or you can pull it down (to 1st) and be driving better sooner. It may actually help your trans to learn faster, especially if you just started pulling a lot of weight. By the way, I don't pull it down from 55 mph. I do it from about 35 mph and I swear I can tell the difference in how the trans works afterward (most noticable when I go from Texas to Utah). I have started the trip (1 or 2 times a year) without doing this just to see the difference.... it appears to work.
Good luck,
Bob


Good luck,
Bob

[KompressorMan]

Brandy,
DON'T DO IT. I completely understand everything that has been said about the TCM being too smart and no damage will be done, BUT...
Yesterday I thought I've got a few minutes and I'd like to get the old pep I used to feel when it was new, so I'll just re-program the transmission. On a level spot of road I slowed to and maintained 50 for a short while then dropped it into first, everything went ok until I got to about 27-28 mph, then whoa. The thing slammed into first and if I hadn't been wearing my seat belt, I have no doubt that I would've ate the steering wheel. It was MUCH to abrupt. The drive line isn't made to withstand that much shock. One thing for sure, I won't do it again.
Good luck
Herb