88 Corvette will not go into overdrive
Thread Starter
5th Gear
Joined: May 2018
Posts: 5
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88 Corvette will not go into overdrive
I have a 1988 Corvette with the WR 4+3 transmission my overdrive was working perfectly fine and then when I started to notice what is the overdrive would come in and out on it’s own and eventually it just stopped coming on any suggestions as to where to look first. Thank you an
Melting Slicks
Joined: May 2014
Posts: 2,893
Likes: 592
From: New Port Richey FL
First thing you need to Figure out whether it is a Mechanical or Electrical Problem.
Have you checked the ATF Fluid?
Is the O/D unit getting the Power down to the Spade Plug to Activate the O/D with wheels turning?
Does the O/D Active Light Come On?
Have you checked the ATF Fluid?
Is the O/D unit getting the Power down to the Spade Plug to Activate the O/D with wheels turning?
Does the O/D Active Light Come On?
Last edited by s carter; May 21, 2018 at 04:37 PM.
Thread Starter
5th Gear
Joined: May 2018
Posts: 5
Likes: 0
Overdrive issue
2 with out putting the vehicle on a lift or jackstands with that be able to run my test light into the vehicle and check while driving with a passenger checking.
3 when the button is pushed twice the overdrive light comes on and pushed twice again it won’t turn off. I do leave I have a small transmission leak that I have to look into this weekend.
The weird thing is is it was working perfectly fine and then one day in the on position it started to come in and out of overdrive and the light would stay on. And finally the light would come on and then no overdrive.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
No real way to check the fluid level in the OD unit. You could remove the fill plug and see if any fluid comes out which would indicate that it is full. Otherwise it would be a good idea to drop the pan, replace the filter and refill using a non-synthetic ATF fluid.
As mentioned, check for power at the wire that connects to the solenoid. As to the button on the shifter, you should only have to press it once to engage the OD and once to turn it off. The voltage check should be done at the solenoid connection so the car should be up on a lift or on jackstands.
Here's a table that shows how the OD units by year are supposed to work. Look at the 87-88 column on the right side for your year.
As mentioned, check for power at the wire that connects to the solenoid. As to the button on the shifter, you should only have to press it once to engage the OD and once to turn it off. The voltage check should be done at the solenoid connection so the car should be up on a lift or on jackstands.
Here's a table that shows how the OD units by year are supposed to work. Look at the 87-88 column on the right side for your year.
Thread Starter
5th Gear
Joined: May 2018
Posts: 5
Likes: 0
Overdrive issue
No real way to check the fluid level in the OD unit. You could remove the fill plug and see if any fluid comes out which would indicate that it is full. Otherwise it would be a good idea to drop the pan, replace the filter and refill using a non-synthetic ATF fluid.
As mentioned, check for power at the wire that connects to the solenoid. As to the button on the shifter, you should only have to press it once to engage the OD and once to turn it off. The voltage check should be done at the solenoid connection so the car should be up on a lift or on jackstands.
Here's a table that shows how the OD units by year are supposed to work. Look at the 87-88 column on the right side for your year.
As mentioned, check for power at the wire that connects to the solenoid. As to the button on the shifter, you should only have to press it once to engage the OD and once to turn it off. The voltage check should be done at the solenoid connection so the car should be up on a lift or on jackstands.
Here's a table that shows how the OD units by year are supposed to work. Look at the 87-88 column on the right side for your year.
