1994 Explorer with 184,000 miles, automatic od.At 55mph the engine should turn 1500 rpm. Recently while driving at a steady 55 mph, it feels like it downshifts and the tach will jump to 2100 rpm. I pull the gear selector out of overdrive and I feel a down shift and the tach will jump up a few hundred rpm more. When I shift back to overdrive, the trans shifts but the rpms drop to only 2100.
Transmission shifts through all gears as it always has, just seems like the torq converter is not locking up when at highway speeds sometime. It will work fine for a time, then act up.
Is this a torq converter problem or a problem in the transmission?
I had the fluid and filter changed and saw no improvement.
Bought this vehicle new and it has been a gem. Would love to get 200,000 miles.

 

I would bet it's an EEC-IV problem. Torque converter lockup is electronically controlled by the PCM. The PCM decides when to engage the torque converter lockup clutch (TCC) based on vehicle speed and throttle position primarily. Engine also needs to be at reasonable temperature; can't be too hot or too cold (or ECt indicating too hot or too cold. 1st step would be to perform the EEC-IV self-tests, correct any faults that come up, then test the above sensors.

 

do you have 4th gear??

if you dont try changing the speed sensor it is $20 at autozone

 

Pancho - what was the verdict on your problem? I have a 2wd 94 sport with 242,000 that seems to do the same thing. I just recently started pulling a 14ft trailer with dirt bikes and ATV's.

Because it is older and I was going to be pulling a trailer, I installed a 180 deg. thermostat instead of the 194deg. stock one. when the old one failed.

I did make one mistake pulling the trailer - I ran in over drive with the cruise for about an hour and the check engine light came on. I sat for 30 min because I assumed I had heated the transmission. I drove it in drive for the rest of the trip without the cruise and had no probs. No engine light since and I have made about 10 two hours trips, but it does take some distance to get it up to speed.

The load weight I am towing is about 2200lbs including the trailer.

Since then the truck builds rpm normally and runs great but doesn't have the get-up-and-go it used to. There is no slip or jerk to the transmission, just feels like the transmission is not delivering power to the rear wheels. This is WITHOUT the trailer.I have always change the filter and fluid regularly.

My engine is orginal, gets the same mileage it always has, and burns no oil at all. Runs good and revs quick and smooth. I just had the exhaust and Catalytic flow tested which showed 0 backpressure.

My cruise control also started to intermittently not work.

Based on some of the reply's here, I wonder if the engine is running to cool and causing an issue with my torque converter??

Anyone have any ideas??

Thanx

 

i think you both should try to change the speed sensor bc my navajo started to do that and the cruise control worked on and off so i changed the speed sensor and had no problems what is happing is the speed sensor it sending signals on and off and the eec cant figure out what speed it is at