Lurch or Bucking Upon Quick Stop

[imported_]

When I come to a fast stop it feels like the tranny is still in a high gear and lurches or bucks the truck forward once. Luckily the brakes hold it back.

I've read about this here before but cannot recall the subject heading to look it up.

Does any one know of the fix?

[hickcox]

I can't remember what heading to look under either but I got it fixed just a little while back.
My complaint was when coming to stop sometimes there is a recoil motion response (like getting rear ended).
To correct the problem they reprogrammed the TCM with update # 000594
And the problem no longer exists.

Hopefully this will fix your problem as well.

[mackin]

An 03 with this problem too?? I would think the up to date software would be in the original program......If it's not that would be ridiculous.....

Your not a two footer are you???

MAC ;)

[imported_]

I'd assume the 03 would come with the latest updates so maybe it's something else.

It's the feeling you get if you fail to depress the clutch when coming to a stop in high gear with a manual tranny, except it doesn't stall.

Also get a little vibration on normal stops.

We'll see what the fix is sometime this week.

Hickox thanks for your helpful reply. Hope it turns out to be as simple as a reflash of the tranny.

Just installed the the WTW Westin Chrome plated stainless step bars. Now my wife and my 4 year old can get in and out much easier.

[FightinTXag]

I experienced this in my '02 many times as well. I wanted to wait until I had a handful of complaints before taking it in. Now it's got 8500 miles and I can't remember the last time it happened. Maybe the adaptive shifting has to "learn" how to do the 2-1 shift smoothly?

[sdaver]

sometimes a low rear tire can cause some locker lash thats similar to to those symptons.....different size tires due to difference in air pressure can cause one side to travel a longer distance that the full side and the locker sees this as a slipping and locks up.......very common with full detroit lockers or nospins as some call them........noticed it once with my 2001 8.1/alli with the g80 diff......it was a low tire........dave :D

[imported_]

sdaver,
I believe it could have been the locker because it had the same dull "thud" feeling as sometimes when they lock in hard.

Maybe during fast stops one wheel grips and the other one remains spinning enough to make it engage - but it seems bassackwards to lock up coming to a stop instead of taking off.

Anyway I tried to duplicate it on around 6, 7 hard quick stops but couldn't.

So maybe it was just one of those things...

[ALLIMAX]

My 2001 and 2003 duramax both had this problem at first. When I bought my 2003 it had a VHS tape that talked about the allison tranny and this very point was discussed. It is all part of the normal learning process of this tranny. This tape was originally intended for the sales people but GM has made it availible to everyone.

[MountainMax]

The tranny is "learning". My 01 did it a few times then quit. I just had some service done that required a reflash of the trans. I'm going through some of the same stuff as when new. Including the "scare the crap out of ya, I've been bumped from behind" lurch.