First Corvette...88' c4 need help!

[Oldskool153]

Hey I have just bought myself a 1988 c4 coupe, it is the first Corvette I have owned (had always wanted one) But I have owned alot of cars for only being 21..most of them have been pre-1980. I actually traded my 70' Dodge Dart for the vette. Anyway it has 112k and the 4+3 trans, seems to run so far so good. my question is this, when I 1st got the vette (one week ago) it seemed like it pulled hard when I would upshift, now it seems that it pulls hard in 1st and when I shift into 2cd, it keeps gaining speed but doesnt seem like it pulls as hard.. is this me getting used to the cars performance or culd something be wrong? I noticed that when I upshift into 2cd the OD light comes on, but when I push the button it doesnt go off.. could that be my problem? or is this in my head.. any advise would be apperciated. and also why wont the OD light go off? thanks

 

[muddywaters]

How are ya? The first thing you should do is service the OD unit (Fluid/Screen). I have the exact same 88 white 4+3 coupe. I tinkered with the OD unit and it only comes in when you ask for it, instead of the computer bringing it in, it's a much better set up ,takes the wear and tear off the Unit by not bringing it in needlessly. As far as the pull goes can't help with that one, but make sure the OD unit is serviced.

 

[Oldskool153]

Thanks, any idea on how much this will cost? Also assuming that the car never had a trans service b4 (i dont know if it has or not) is it bad to service it with 112k? I have heard stories of overdrives failing after a trans service....

 

[muddywaters]

Thanks, any idea on how much this will cost? Also assuming that the car never had a trans service b4 (i dont know if it has or not) is it bad to service it with 112k? I have heard stories of overdrives failing after a trans service....

I got the kit from Ecklers, around $20 plus fluid. I can't see where servicing a OD unit, engine, tranny can cause it to fail, someone did something wrong or the unit was about to take a crap anyway. My 88 wasn't serviced judging by the build up on the magnet, it has 58,000 miles on it. You have to dress/straighten the pan so it doesn't leak, the book shows silicone sealant not a gasket. Mine leaked after I serviced it the first time, I dropped the pan the second time and got rid of the gasket and used silicone, problem solved, I filled the OD, ran it for a while, topped it off. Runs great.

 

[vetteoz]

I tinkered with the OD unit and it only comes in when you ask for it, instead of the computer bringing it in,

Start car , hit O/d button .(if working )
It disengages the ECM control of the O/d.
Car will not go into O/d until you push button again.
Pop the clutch in when shifting O/d in / out it ; takes the load off.O/d filter is same as Ford FMX trans.

If the button is not controlling the O/d then there may be a fault in that circuit .
The fact that the O/d is engaging means that the ECM control side (ECM / relay / solenoid ) is working fine

Corvette 4 + 3 Overdrives

 

[Oldskool153]

thanks for all the help guys, I spoke to a guy at the local Corvette repair shop and I told him that my car will not shift out of OD when I hit the button or when i accelerate hard Like its soppussed to, he seems to think that Either the OD button on the shifter or the OD switch in the trans isnt working, I guess its better to be stuck in OD than not in OD but eitherway I want to get this fixed, the local guy wants $98 just to tell me which switch is bad.. not to sound cheap but at 21 years old I dont have $ to throw away, is there a way to diagnoise this myself? thanks