NEED HELP 1995 GMC C1500 5.7 TBI REBUILT 4L60E Limp Mode No Codes Stuck In 3rd Gear

350TBI

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Truck has almost 300k miles engine runs great. I just had the transmission rebuilt from AAMCO less than a month ago and its been back 2 times already. I honestly dont think they have a clue what the issue is. I was driving to work one morning a few weeks after the rebuild and about 10 mins away from my house I was at a red light when i hit the gas the truck barely took off and stayed in the same gear. When I stopped again it started driving like normal. After work as soon as i started my truck and put it in drive it didnt move an inch untill i hit the gas and again stayed in the same gear reving around 2000 rpms with the pedal to the floor. When i got home I looked underneath and noticed fluid coming from the VSS on the tailend of the transmission. There was fluid that looked like it was coming directly from the plug where the harness goes into the VSS in the electrical connector. I took it back to AAMCO they replaced I got my truck back and two days later the same issue. I took it back and the replaced the shift solenoids. Truck drove fine for 2 days then now im back in the same boat. I didnt drive it much after i got it back from them initially if i did i might have brought it back the same day. Im thinking the fluid in the harness possibly shorted out the harness or ecm. But im no expert or experienced tech. If anyone has anything they may know that might help id really appreciate. im not seeing much info on this specific situation.
 

1997

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x2 that sucks.
95 is a 1yr only trans ... did they actually rebuild yours or replace?
OBD1 can set codes without the check engine light coming on, no codes for sure?
limp mode, only stays in 3rd, that's wierd.

look for code or symptons in here:
https://shop.ukrtrans.biz/wp-content/uploads/catalogs/4L60E_80E_CODE_BOOK.pdf
follow their troubleshooting flow chart, should point you (and shop) in the right direction.
it worked for me, good luck.
 

Erik the Awful

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There's lots of techs who can pull apart an auto and stick it back together, but there are precious few masters who can build them to run reliably. Keep taking it back until they either get it right or give you your money back.
 

350TBI

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x2 that sucks.
95 is a 1yr only trans ... did they actually rebuild yours or replace?
OBD1 can set codes without the check engine light coming on, no codes for sure?
limp mode, only stays in 3rd, that's wierd.

look for code or symptons in here:
https://shop.ukrtrans.biz/wp-content/uploads/catalogs/4L60E_80E_CODE_BOOK.pdf
follow their troubleshooting flow chart, should point you (and shop) in the right direction.
it worked for me, good luck.
Thanks for the info it’s much appreciated
 

Supercharged111

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Sounds like a power or ground issue to me. When you unplug the harness on a 4L60 and drive all you get going forward is 3rd gear.
 

350TBI

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Truck has almost 300k miles engine runs great. I just had the transmission rebuilt from AAMCO less than a month ago and its been back 2 times already. I honestly dont think they have a clue what the issue is. I was driving to work one morning a few weeks after the rebuild and about 10 mins away from my house I was at a red light when i hit the gas the truck barely took off and stayed in the same gear. When I stopped again it started driving like normal. After work as soon as i started my truck and put it in drive it didnt move an inch untill i hit the gas and again stayed in the same gear reving around 2000 rpms with the pedal to the floor. When i got home I looked underneath and noticed fluid coming from the VSS on the tailend of the transmission. There was fluid that looked like it was coming directly from the plug where the harness goes into the VSS in the electrical connector. I took it back to AAMCO they replaced I got my truck back and two days later the same issue. I took it back and the replaced the shift solenoids. Truck drove fine for 2 days then now im back in the same boat. I didnt drive it much after i got it back from them initially if i did i might have brought it back the same day. Im thinking the fluid in the harness possibly shorted out the harness or ecm. But im no expert or experienced tech. If anyone has anything they may know that might help id really appreciate. im not seeing much info on this specific situation.
Apologies for the delay new baby at home. Truck has been running fine but I’ve only taken it to and from work. They replaced the neutral safety switch I believe it’s called. They also rerouted the cooling in some way because it was getting hot causing the “limp mode” which they never confirmed why they didn’t replace it initially. I wasn’t too sure on the cooling rerouting either but as I said no trucks running no leaks and seems to be a solid rebuild.
 

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1997

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Congrats on new baby, good to know you got it sorted.
 
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