4=3 Overdrive Solenoid Cleaning
Thread Starter
Racer
Joined: Mar 2004
Posts: 252
Likes: 1
From: Troy Illinois
4=3 Overdrive Solenoid Cleaning
I have been having trouble with my overdrive engaging. Sometimes it works fine and other times it will not engage right away, or at all. When it doesn't engage the light doesn't come on and the light always comes on when the overdrive engages. I replyaced the relay and cleaned the connector a couple of years ago. On 10/21/07 a post "Doug Nash 4 + 3 Bhatreakthru" describe how to clean the solenoid that activates the overdrive. The problem he was trying to solve sounds similar to mine so I thought I would give it a try. Has anyone done this and if so can you give me some pointers?
Safety Car
Joined: Jan 2004
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Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
I recently had the exact same problem. I pulled the plastic cover off of the relay, pushed the relay in with my fingers to see if the OD light came on. I could stand next to the drivers seat and push in the relay and see the dash at the same time. The light came on. So there was no signal to the coil in the relay. So this told me I had problems with the OD switch, switch circuit, ECM or wiring from ECM to relay. I decided to hook the OD switch directly to the relay. The switch grounds the coil to the relay, energizing it, and no more OD problems. Every time I hit the switch, I have overdrive. A good mod. If your light is not coming on, it is not the solenoid.
Last edited by powerpigz-51; Oct 28, 2010 at 01:29 AM.
Team Owner
Joined: Jan 2003
Posts: 20,253
Likes: 219
From: Summerland B.C. Canada
Also, the ECM needs to see the correct parameters before it will allow OD. Coolant temp is one of them, so if your trying with the engine too cold, you will not get OD.http://www.5speeds.com/43table.htm
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
If the light doesn't come on, cycle the switch back and forth a few times and see if it is just a scratchy connection.
also, check your temps on your temperature gauge, if the temp is too low then the O/D will not come on
also, check your temps on your temperature gauge, if the temp is too low then the O/D will not come on
Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
This begs the question and I have never seen an explanation as to why the engine has to be a certain temp for the ECM to allow you to switch on the OD? If it is a simple automatic 2 speed transmission, what is the reason for this? And why won't it let you go into OD AFTER romping on it? Now that mine is overriding the ECM, I would like to know.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
It's a warming up feature. I guess if you were running too low RPMs it wouldn't allow the car to warm up to proper temps.
And all the years are different temps...so the '84 is lower than the later years.
And all the years are different temps...so the '84 is lower than the later years.
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Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
Prevents you loading up the engine until engine is up to operating temp.
Q
Why no O/d in 1st gear?
Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
Why no first gear OD......hmmmm....other than why you would need it in first gear, maybe the torque multiplication of first gear could damage it in some way. First gear burn outs and switching into OD sounds like fun! lol
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
The I got a hold of the car and went after the over heat issue ASASA (as soon as summer arrived).....once I cleaned the radiator and replaced a failing water pump...new hoses, new coolant etc.....the damn thing started running too cool.
I'd be driving down the freeway and the temps would start dropping.
As soon as they reached 159°, the O/D would drop out.
At 80mph (standard speeds here in SoCal) it is pretty hairy when it just drops out....scares the crap outta me...
so yeah, the computer was reading those low temps and doing what it was supposed to do....take it out of O/D
Heel & Toe
Joined: Oct 2010
Posts: 20
Likes: 0
No overdrive on my 85 4+3 ?????
My overdrive light comes on when it reaches the correct temp but will not go into overdrive. I replaced the relay for the heck of it (same part number as fuel pump relay). and still no OD. What is the next thing to try?????? Please help
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
If correct , check wiring to plug on side of O/d.Common for connector on plug to break or have bad connection
Put 12V on terminal F of the ALDL connector and see if you can hear anything click inside O/d indicating solenoid is operating
Last edited by rodj; Oct 29, 2010 at 10:28 PM.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Terminal F of the ALDL connector under the dash that you use to check engine codes
http://www.corvettebuyers.com/c4vettes/codes.htm
http://www.corvettebuyers.com/c4vettes/codes.htm
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
This is why folks tell you to check the level of fluid.....no fluid....no pressure to that switch.
CentralCoaster begged me to "pull the pan" and see what was going on with my 4x3.....but I resisted out of fear.
Once I got the pan off and after running everyone ragged with questions about the 4x3....and after diagnosing that my issue was the pressure switch.....
I bought a pressure switch and had it ready to install.
Finally...weeks later, I pulled the pan and what did I find?
The beige colored spade connector had fallen off the pressures switch
Read the thread as I put a drain plug on my 4x3 pan while I was there
http://www.theforumlounge.com/1984-c...4x3-t8555.html
Heel & Toe
Joined: Oct 2010
Posts: 20
Likes: 0
wow!!! Good post. Thanks for the advice. I will definately pull the pan thursday night and check. I have looked on line looking for a place to buy a new pressure switch and solenoid if I needed them but cant seem to find them anywhere. any place I can look and any idea how much they are ?????
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Brian @ SK Speed is the 4+3 Guru for service and parts
http://www.skspeed.com/
Keep this address for future reference;
one of the few left who knows what the inside of a 4+3 looks like