tranny issues

[1hotduramax]

Hey Guys,
I have a 2001 chev 2500hd with 6.6 duramax and allison transmission.

I've had this happen 2-3 times now I pull up to stop and when I go to take off it acts like it's not in gear just for a split second then it takes off like normal after a little bump.

I've noticed this on a few chevy gas rigs i've driven over the years also.


Any ideas

 

[Mike L.]

Check fluid level.

 

[1hotduramax]

3/16" below top notch with w/hot transmission

 

[1hotduramax]

Is that too low or should it be kept right up to full on a hot check?

Any other ideas?

 

[paint94979]

Is that too low or should it be kept right up to full on a hot check?

Any other ideas?

sounds fine

 

[Mike L.]

Check for codes with a Tech 2. You have the earliest Allison and they had some defects that should be addressed.

 

[1hotduramax]

I've checked quite a few times with the efi live scan tool never any codes.
Does the tech 2 have more capability with that?

I have seen a service bulletin that may apply not sure.

 

[Dave L Weaver]

Hey Guys,
I have a 2001 chev 2500hd with 6.6 duramax and allison transmission.

I've had this happen 2-3 times now I pull up to stop and when I go to take off it acts like it's not in gear just for a split second then it takes off like normal after a little bump.

I've noticed this on a few chevy gas rigs i've driven over the years also.


Any ideas

I came on here to post the same problem. Same year truck n doing the same thing....come to a stop n get on the throttle n seems like its not in gear then suddenly grabs! Every thing shifts fine n temps r normal. Hope sombody has a clue what the problem is!!!!

 

[Mike L.]

These problems could be draggy shift solenoids that are slow to respond. You cannot check them unless you have a solenoid dyno and see what is going on. Solenoids are cheap at Allison and easy to change Go buy three of them and see what happens.

 

[1hotduramax]

Thanks for the tip, I'll look into that.

 

[1hotduramax]

Problem solved

Check for codes with a Tech 2. You have the earliest Allison and they had some defects that should be addressed.

Thanks Mike,

Took truck in to dealer and had TCM programming updated and put into fast learn.

It's clicking off nice crisp little shifts alll the way up and down. Also seems to downshift from 2-1 a little quicker when pulling to a stop so it's ready when I hit the pedal to go!