I have a 1990 4x4 xj with 4.0L & automatic trans. The problem is, intermittently the trans has delayed shifting (engine revs higher) from 1st to 2nd. From 3rd to 4th is just fine. sometimes the shift from 1st to 2nd is just fine as well. Any ideas? Thx for any help!

 

Hi and welcome to CF from Tj...How many miles on the Trans/fluid?

 

There is a servo in the AW4 that controls that 1-2 shift. It could be getting worn out. If you drive around a lot like crawling trails for instance with your tranny selector in your lowest gear which in the AW4 is 1-2 because it doesn't give you the ability to select 1st and 2nd gear individually. Having your gear shifter in that position and crawling around will cause your tranny to constantly be hunting between 1st and 2nd gear. If you or the previous owner of your Jeep did this alot it could cause that 1-2 servo to wear out and cause slipping or a pause between those two gears.

 

I unfortunately don't know. The fluid is not filthy but it's not clean/new either. I was planning on changing it soon.

 

Is the servo a tough fix or replacement? Could it be the TCU?

 

Honestly bro I've never had to do it to my rig yet. Sorry I can't help you with that. Awhile back I found a way to put in a toggle switch and manually turn my TCU on and off. If you come to a complete stop i.e. your tranny is in 1st gear then I flip the switch turning my TCU off. Then, I can crawl around on the trails all day without the tranny stuck in 1st gear until I flip the switch back turning my TCU back on and she shifts automatically like normal again.

 

bump...anyone else with any ideas I changed the transmission fluid & filter and installed a new TPS. Still the same problem.

 

what kind of fluid are you using.?

 

Dex III