2001 2500HD Duramax Allison Transmission issues? - Chevrolet Forum - Chevy Enthusiasts Forums

2001 2500HD Duramax Allison Transmission issues?

Nyxian's Avatar
New User
Awaiting E-mail Confirmation

Join Date: Dec 2011
Posts: 1

December 23rd, 2011, 11:17 AM   #1  
2001 2500HD Duramax Allison Transmission issues?

Hi there, having a bit of a sporadic issue with my Silverado, here is the best description I can give, I have not been able to find out what would be causing this, so any info on what you would call it would be great.

Occasionally the truck won't accelerate, or shift into a higher gear, and instead gets stuck at a certain speed. It has twice gotten stuck not going faster than 65 MPH, it accelerates TO 65, however does not get over it, and at 65 it is clearly at a high RPM and should be shifting up. If I drop it down to 30 or 40, and then floor it, there is also no acceleration kick like there normally is, it instead accelerates very slowly to 65, and then caps at 65.

I've had this happen twice in about the past 30 days and worried it might get worse. In the two times it has happened, pulling over, putting it into park, off, on, and then back into drive has resolved it.

Transmission fluid is kept up, clean, and at proper levels. Oil is clean, at proper levels.

Any help on simply identifying the issue would be great, thank you!

Let me know if you need any more descriptions or info about the vehicle, I'll be checking the thread regularly.

chouder1's Avatar
CF Beginner

Join Date: Apr 2014
Posts: 1

April 19th, 2014, 5:49 AM   #2  
ihave a2001 duramax 2500 w/Allison trans , will not upshift and bangs into reverse. trans indicator light goes goofy, put in new park / neutral switch and that took care of it.

Allan In NE's Avatar
CF Pro Member

Join Date: Dec 2011
Posts: 673

April 19th, 2014, 7:25 AM   #3  
The problem isn't with the transmission, I can just about promise you that. These things have so many safteys built into them that it is almost impossible to tear 'em up. The computer is protecting the transmission.

The fact that it will "reset" and operate okay with an ignition cycle proves that.

If your diesel fuel/air filters are good, then get this guy to a dealer or competent repair man, as you are dealing with a drivability issue.


kyle85's Avatar
CF Beginner

Join Date: Jun 2014
Posts: 1

June 6th, 2014, 10:14 AM   #4  
im having the same issue

I'm having that same issue. Did you ever get any answer as to what was wrong? Thank you in advance!

Search this Thread