Shifts in and out of overdrive!? Check Engine light is on..

[markmackie]

Greetings Team,

I have a 93 4x4 Eddie Bauer 4.0L with 206,000 miles.

New problem is that driving on the highway in OD, the tranny will shift into 3rd when it should not, then after 2-3 seconds it shifts back to OD, and it keeps doing this in/out shifting over and over.

Of course I put the shifter in 3rd and continue on, but I need to fix this since my 25 mile commute is all highway at 70+ mph.

Also, in conjunction with this event, the check engine light came on, and is staying on from the moment I turn on the engine.

Tranny is what I know the least.

Any thoughts on what has failed, or is failing?

Thanks,

Mark

 

[cculter]

First I would check the level of fluid when the veichle is running. Might be low, if not contact Glacier991 on this forum, his knowledge of transmissions is very helpful.

 

[MrShorty]

1st thing I would do with the check engine light on is pull codes from the computer. The computer controls 3-4 shift, and whatever is causing the CEL to come on could easily be causing the computer to shift in/out of 4th gear. If you want to try pulling codes yourself, see my "notes on pulling EEC-IV codes" in the EEC-IV forum.