Allison Trans with no Reverse

Really Old Guy

New Member
Hi Everyone,
I have a 2001 Chevy 2500HD that I use to tow my Jeep. I have owned it since it was new. For almost the whole time I have owned it, I have had to put it in reverse and wait 10-45 seconds for reverse to engage. The last time it got used the wait was more like 15 minutes. My brother had a 2006 that did the same thing. Anybody have any ideas regarding the cause and how to fix it? If not, does any body know of a transmission shop that will actually repair it rather than a complete rebuild?
 

1969honda

Well-Known Member
Supporting Member
Location
Cache
Possible converter drain back? I tried googling your symptoms and it seems there was an early GM/Allison problem around 2001/2002. It's possible this is your problem and over time it's cause minor damage that circuit in the transmission. When was the last time you serviced the transmission? How many miles and what kind of use does it normally see? (heavy towing, programmer, daily driver, etc.)

@zmotorsports (Mike) might have some better insight or has seen a similar issue before. I'm not terribly familiar with the Allisons but it sounds like a fluid volume issue on that hydraulic circuit.
 

Really Old Guy

New Member
Possible converter drain back? I tried googling your symptoms and it seems there was an early GM/Allison problem around 2001/2002. It's possible this is your problem and over time it's cause minor damage that circuit in the transmission. When was the last time you serviced the transmission? How many miles and what kind of use does it normally see? (heavy towing, programmer, daily driver, etc.)

@zmotorsports (Mike) might have some better insight or has seen a similar issue before. I'm not terribly familiar with the Allisons but it sounds like a fluid volume issue on that hydraulic circuit.
It has 150k on it now and the last time it was serviced was at 25k. I read something about a fluid pressure switch and the switch is easily available on line. Could that be the type of thing to cause that problem?
 

anderson750

I'm working on it Rose
Location
Price, Utah
125k without service is a lot of miles. With that said, if you are only seeing a problem in reverse and not forward gears it makes me think that it could be a non fatal problem. However you are WAY overdue for a service.
 
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