Ok I need help! I had my overdrive unit rebuilt, and all was fine for about 6 months, then I started to have a battery drain problem that I have yet to sort out ( I just disconnect the battery every night) I put my meter on the battery and it shows no drain yet if the car sits a few days the battery goes dead ( I did change out the battery) anyway this is not why I am writing, I just want to give a background into what is going on with the car as the low voltage problems I have had may have something to do with the overdrive problems, oh yeah by the way I have a 86 corvette TPI 4+3 tranny. Anyhow the problem I am having is that I cant get the LOW gears, thats right The LOW gears. My experience is anytime you have overdrive problems with these cars all you get is the 4 speed manual transmission without the overdrive. well since the last time the car sat ( about 2 weeks) I jump started it and took it to the gas station for fuel and noticed right off that even in 1st gear ( yes 1st gear ) the overdrive is trying to kick in if you try to manually keep it in the low gears it jumps in and out of overdrive in all gears. So you need to keep it in overdrive mode (it still want to shift up and down in 1st but all of the other gears are fine in overdrive mode.) I cannot at all get it to stay in low mode. I guess what I am wondering is could my battery problems have spiked the computer so now it is messing with my shifting? I printed out a tech page for bypassing the ECM to allow for manual shifting and may go that route if need be but if changing out the computer will fix my problem I would rather go that route as I have 2 good computers here at the house. and the way it sounds changing out the shift button could be a pain in the ***! I appreciate any advice on this matter, Thanks alot! Oh and please if you have had this problem and have a good idea what it is please feel free to email me at jcays@***.net

 

A couple ideas.

1. The shifter switch wires have become exposed and are short circuiting.

2. The O/D relay wires have become exposed (a very common problem) and are short circuiting. It is one of 2 relays under the wiper motor area and along the firewall.

If it is happening in 1st I would almost lean towards #2 because the ECM hardly hardly ever attempts to use O/D in 1st; only in very special conditions.

 

scorp...Thanks so much for your reply hope it works sounds much better than the thoughts I was having! Thanks again!

Jon

 

Thanks one more time that did fix my problem when I pullee the connector out of the relay to look at it there were bare wires everywhere and they were twisted and laying on one another. Seperated them and taped them individually ( till I can get a new harness connector) then taped them all up and problem is SOLVED!! Thanks again!

 

Read the "cautions" section on wiring:

http://forums.corvetteforum.com/showthread.php?t=956100

 

Great, you're welcome. Those things are a pain in the azz! The wire insulation pulls back over the years leaving you with that mess.