So I like many others am having an issue with the Overdrive in my newly purchased 94 JGC 4.0 4x4. It's bone stock so no lift & large tires or anything out of the norm. It works fine for about 15-20 minutes then will kick in & out of OD while on the freeway. I've checked and adjusted the cable and also changed the TPS (old one had a crack in it anyways) after reading a bunch on here. Still having the same issue. Is there any one reason this happens or can it be a plethora of different issues causing this? Is there any sort of temp sensor that controls anything on the trans?

Thanks,
Miles

 

No one? Any Ideas? When it comes to Diffs I know everything there is needed to know but on transmissions I could really use some help

Thanks,
Miles

 

You talking about the overdrive gear or the torque converter lockup?

Both are electronically controlled, the solenoids are driven by the TCU based on inputs from the TPS and the trans speed sensor, IIRC. I wonder if you have a solenoid acting up when it gets warm? Might check the resistance while it's good and warm. Should be in the 12 ohm neighborhood.

 

My 90 was doing something like that. I guess I have other issues, but setting my cable with no play and no tension seems to have made it clear up.

 

I'll recheck my cable and check the solenoids.

Thanks,
Miles

 

Well after checking & adjusting a million things and having my transmission guy tell me it's electrical. I decided even though all the stuff checked out ok using my voltmeter I would try replacing the VSS and NSS being that I could get both brand new for under $35 for the pair. I started with the Transmission VSS and guess what... Problem solved. I am assuming that under the higher rpm of the reluctor the signal was getting weak or just confusing the trans control unit.

Miles

 

Do you mean the TPS? (on the throttle body)

 

guessing he means the vehicle speed sensor.

 

Duh...Thanks! (one of the two sensors on my Jeep I haven't checked)