sledneck800
10-23-2005, 01:22 AM
Hello Guys I just picked up a 1996 chev 1ton crew 4x4 with 254000 km. Im happy with the truck except for when going up a longsteep hill when im in 4th gear and and the tranny kicks down into 3rd gear it will stay in 3rd and never go to 4th again ... even when i crest the hill and go down it still wont ever switch up to 4th. When i stop and switch the truck off for about 1 min it will resume normal operation and i will get 4th gear again. On a seven hour trip between Prince George and Vernon BC there were only 3 hills steep and long enough to make it do this, but it still is a pain in the butt. The tranny does not slip in any gear. The previous owner had taken it to lots of mechanics and they all couldnt find the prob. Their diagnostics were always vague and involved a "new tranny". Even the GM dealership gave up on this truck. Any help would be greatly appreciated. thanx.:ro)
edzzed
10-23-2005, 02:25 AM
g'day you should update your signature 1st. at 254000 kms would you say it is the original tranny. if so you did better than me at 140000. 3600.00 at aamco. might be a loose wire from the ecm. gets hot and maybe makes a bad contact, just a guess.
thefermanator
10-23-2005, 02:36 PM
Yours unit is one of the ones that had the ground issue I believe. Check for threads on bad grounds with the 4L80 trans. Hopefully Mike L. will chime in on this one.
69camarox
10-23-2005, 10:37 PM
check codes first but it is probably a lockup issue if this trans shows a 200 rpm slip for 2 seconds in l/u it will default to no 4th and no l/u .these trucks tend to wear out the bushing in the stator support and then the lockup clutch in the converter wears out if you take out the trans and replace the bushing and converter it will most likley fix your problem if it is original trans it would be a good idea to go through the entire trans this trans tends to wear alot of parts
Mike L.
10-25-2005, 12:12 AM
I believe the problem is worn teflon rings on the center support. The 4L80 is a wonderfull trans but, anything over 100K miles is suspect. Diesel engines tend to beat the snot out of them.
sledneck800
10-25-2005, 01:57 AM
Thanx for the info guys.The code only shows up when it actually happens and that is hard to get as it only usually happens on long trips and long hills. I have another question I have the exact identical truck 1998 except it has a 454 motor... would the tranny fom the 454 work in the diesel? maybe with a different converter??? thanx.:)
69camarox
10-29-2005, 07:50 PM
trans is the same converter is diffrent stall but you can use it too i have with no problems