fixing overdrive question

[eddiebexplorer]

i have a 93 X and the overdrive went out and i did not have time to fix it so it was drivin without overdrive for a few months when i finally got around to fixing it i found out that there was an open in the wire to the 3-4 shift solenoid so i fixed that and it shifted into od once and didnt after that.

so my question is that i have to change the tranny filter and fluid soon so can i possibly clean out that solenoid if its gummed up or do i have to get a new one and does anybody know where to get one. I know fore sure that the solenoid is getting power.

thanks

 

[Masterd]

I believe they are so close to the exhaust that over time they literally cook. The rubber gets hard.

 

[MrShorty]

I know fore sure that the solenoid is getting power.

But is it seeing ground? The computer acts as a ground side switch. If the computer can't/chooses not to apply ground, then it won't shift into 4th. Where you've already found one fault in the circuit, I'd make sure there are not other faults in the circuit.

I believe the screen that is on the 3-4 shift solenoid can be cleaned, if that is the reason it won't shift.

 

[eddiebexplorer]

can u back probe the connector to the solenoid and ground it out to see if the solenoid clicks and if the solenoid is working but it wont go into 4th is there a problem with the computer or am i totally wrong with that

 

[MrShorty]

You can do that, but be sure you understand your wiring diagram so you don't ground the wrong wire. With these computers, you don't want to accidently do something that will ruin them.

Personally, I prefer to put a voltmeter across the solenoid and just watch what the computer is doing. Use the output state test to get an idea of what to see (and to see if the computer is even capable of commanding the shift), then road test while monitoring the voltage drop across the solenoid.

 

[eddiebexplorer]

ok i will do that but how are u goin to make the solenoid work through the computer when ur not test driving it (is that a dumb question) how would u command the computer while ur watching the solenoid

 

[MrShorty]

My "notes on performing EEC-IV self-tests" thread in the EEC-IV forum describes how to enter the output state test mode.