I think i have a problem with my OD

[swordfish25]

I have a 91 explorer XLT and i think the overdrive does not work . when i get on the highway my rpm's are always really high , in 3500 to 4000 range ,it just wont kick down . I talked to a friend and he said the overdrive is the first to go before the tranny go's . Is this true , or does anyone have an idea what its is . its an automatic ... thanks for your time

 

[IAmTodd]

Sounds like no OD. Does you OD Off light flash or anything. Do first gens even have an OD off light??

 

[swordfish25]

There is no od light its all manual

 

[swordfish25]

when i drive i can go from drive to od with on kick down ,and its kill my gas mil. with no od

 

[IAmTodd]

I'd get that fixed then. Definetly no OD.

 

[MrShorty]

3-4 shift on the A4LD is electronically controlled, as well as torque converter clutch (TCC) lockup. Are you just missing 4th gear, or does the TCC not lockup as well? If it's just 4th gear, there's probably about a 50:50 chance the problem is in the EEC-IV electronics. Because it's usually easier to check out and repair problems in the EEC-IV portion, I would check that out first.
Start with the EEC-IV self-tests. Then get a wiring diagram and make sure the 3-4 shift circuit is intact.

 

[Opera House]

I wouldn't say 50-50, but if you instantly lost both TCC and OD it could be an electrical problem. The OD planetary breaks a weld and the OD star washer shears. The only good news is if you are adventurous, the OD section is unbelievably easy to work on and cheap. Dropping the tranny is a real pain. The proof will be in the pan. You can still do nothing and it will probably go another 20K.

 

[swordfish25]

thats great advice , so if i do drop the pan what exactly would i be looking for ?????or how would i do eec-IV self test

 

[swordfish25]

i really love the explorer but i have never worked on them before so any help would be great

 

[swordfish25]

i am not 100 percent sure , but i think i am just missing 4th gear

 

[MrShorty]

Quick and easy description of the KOEO test is at www.fordfuelinjection.com www.dalidesign.com/hbook/eectest.html has complete instructions for both the KOEO and KOER tests.
Quick test to see if the TCC is locking up. While cruising at a steady 50 mph , or so, transmission in 3rd or 4th gear, tap the brake with your left foot while maintaining steady throttle with your right foot. Tapping the brake signals the computer to unlock the TCC. If the TCC is locking, you should see a jump of a few hundred RPM on the tachometer.