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Transmission shift problem while towing ?

kjzeusman

Full Member
Joined
Sep 1, 2007
Messages
35
Location
Canada
I have an '04 Avalanche with 30,500 miles on it.   I noticed today when pulling my boat that when I take off from a stop position there is a significant jerk in the vehicle when I first accelerate (and I'm not hammering the gas pedal at all - this is just normal acceleration).   The best way to describe it is the same feeling you'd get if you rev'd the engine up with the vehicle in park and then dropped it into drive; you'd feel a significant clunking / jerking in the transmission.

This happens primarily from a stopped position, and more so when I'm towing my boat.   I have also noticed intermittently at lower speeds that the transmission will occassionally shift hard i. e. there is a definite grab / jerk when it shifts.   Unfortunately this doesn't happen all the time; in fact, the majority of the time it seems to shift just fine. . . . .


Any ideas ?  Are these early warning signs my transmission is on its way out ??
 
that doesn't sound good, have you ever changed the fluid on it?
if not, now might be a good time to drop the pan and see what's in there
 
kjzeusman said:
I have an '04 Avalanche with 30,500 miles on it. ? I noticed today when pulling my boat that when I take off from a stop position there is a significant jerk in the vehicle when I first accelerate (and I'm not hammering the gas pedal at all - this is just normal acceleration). ? The best way to describe it is the same feeling you'd get if you rev'd the engine up with the vehicle in park and then dropped it into drive; you'd feel a significant clunking / jerking in the transmission.

This happens primarily from a stopped position, and more so when I'm towing my boat. ? I have also noticed intermittently at lower speeds that the transmission will occassionally shift hard i. e. ?there is a definite grab / jerk when it shifts. ? Unfortunately this doesn't happen all the time; in fact, the majority of the time it seems to shift just fine. . . . .


Any ideas ?? Are these early warning signs my transmission is on its way out ??

I would say so. Good thing is you should still be under warranty. Take it to the dealer now and let them document the problem.

Butch
 
Do you have it in Tow/Haul?

Do you have 4x4 or 4x2?

does it do it without trailer or with different trailers?
 
I didn't try Tow/Haul mode, although I tried shifting to third gear and it seamed to help.   I haven't tried other trailers only because I don't have easy access to any.   I think my boat & trailer are around 2000lbs. . .

Oh, and I have a 4X4.
 
See if trailer has slop in hitch... you will feel something..

Tow/haul helps when towing as it stays in gear longer...
 
ygmn said:
See if trailer has slop in hitch... you will feel something..

I would suspect that first..I get the same sisation when I pull my boat. If you look at your reciever that goes into the hitch you will noticed that the hole is oversized a little for pin alinement. Also if you have too small of a pin this exagerates the feeling....plus check the correct ball size. All of that together will give you that jerk when you take off...it does for me.....one thing that helped me is getting the max diameter pin that will fit through the hole.
 
Great points.   I never really lookied at the pin & hole size, but will definetely check it out.   I'm pretty sure I have the correct ball size (2") [insert ball jokes here] , but again will check to make sure.

Other question:  do you find that generally the Avalanche tends to shift a bit harder than other vehicles?  For example, my wife drives a Ford Freestar and you can't even tell when that puppy shifts gears - it's as smooth as silk.   On the AV, you can definetely notice when it shifts - not to the point where I think there's something wrong (other than what I've talked about here related to towing) but the Av certainly doesn't shift as smooth as the van. . .

Just curious  ???
 
Shifting depends on how you drive as the AVY has a learn procedure in the Engine computer to control how the tranny shifts.

so if you tow alot or drive hard..
it will shift quicker...

if you drive very gentle (ie No Pedal Stomp) then it will learn to shift smoother...

Try this..

disconnect battery for 5 mins or so...

this reboots puter and allows it to relearn your driving style
 
Cool - I didn't realize the transmission shift points were controlled in that manner.

So are you certain that disconnecting my battery will not cause any other issues (sorry - I'm a newbie). . .
 
kjzeusman said:
Cool - I didn't realize the transmission shift points were controlled in that manner.

So are you certain that disconnecting my battery will not cause any other issues (sorry - I'm a newbie). . .
you will have to reset clock..

should remember the presets.

check the manual on how reset those

Ps Welcome to the club...
 
Awesome.

Thank you very much for all the help and guidance - very much appreciated !!

:)
 
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