Twice rebuilt and still not fixed transmission

gmc
envoyxuv

#1

HELP! I have a 2004 GMC Envoy. About 4 years ago I unwillingly ran over a boulder that was placed in the middle of a winding back road. It cracked my transmission pan, and stripped my fourth gear. I had it rebuilt, only to have issues a year or two later, backing up hill, as well as shifting and idling. So I brought it to AAmco, and they said that the first rebuild was horrible, and that they would do it better. I then had it rebuilt again by AAmco. Now two years later I am having issues again. No one seems to know what’s wrong. The car’s service engine light comes on after driving for an hour or so on the highway. When I come to my first stop after exiting the highway, the car jolts forward as I start off from that stop. The car continues to slam into gear until the car rests. Also my transmission fluid gets dirty way to quickly. I am changing the transmission fluid every other oil change. I don’t know what to do… I don’t have the money, or the time to keep messing around. Any ideas


#2

Well sorry but what’s wrong is you brought it to AAMCO (all automatic transmissions must come out). You are going to have to take it to a real transmission shop and have it overhauled again. Or it could be just electronic this time but you need to go to a real transmission shop or dealer.


#3

Because the first transmission was damaged due to an impact, the case may have some sort of damage that would make yet another rebuild short-lived. A transmission swap would be my next option, and, since you’re low on funds, a salvaged transmission would be an economical option.


#4

Scan the codes when the light is on and write them down, this might provide a clue as to what the problem is.

In cases like this look at the expensive parts in the trans that rebuilders never want to buy like the valve body or the pressure sensor assy.


#5

You should get and report the error code(s) - but note that this can easily have codes that “hide” from generic code readers. However, between the hard shifting and dirty fluid it seems that it is slipping. The hard shift is from the computer maxing out the line pressures to reduce/prevent slip. My guess is that a diagnosis will not make you happy.

If you want to save this vehicle I would just take the plunge on a complete remanufactured unit from a reputable source who provides something like s 3/36 warranty


#6

I have to agree with @BustedKnuckles here. The transmission was damaged and I don’t think any transmission rebuild is going to return it to a reliable condition. BTW…I’m not defending AAMCO here because their reputation is well known and it’s not good by any means.


#7

I didn’t really address the lack of funds issue. What you do depends on how dire things are. In the long run a warranted reman is best if you can scrape that together. The salvage yard option is a good route, and though it contains unknowns I would consider it if you can scrape that together.

But if the money situation is that bad and you can scrape almost nothing together right now, I would actually add a bunch of Lucas transmission “fix” at the next fluid change. This doesn’t “fix” a thing and I would never say to do this on a transmission you planned to fix. But once the thing is toast (which yours probably is) then all you really risk is the cost of the bottle. I did use it once in the past, with reasonable results to, to limp along a GM transmission that I was not going to fix.

I would also consider putting a transmission cooler on it since those are pretty easy to install and not very expensive and this seems to act up after having gotten plenty hot.

Of course, all of that is said without knowing what an actual diagnosis would find.