02' Explorer Transmission Questions

[CommandPresence]

Hey all. I have an 02' Ford explorer. It has 148k Miles on it. I had the torque converter, fluid pump changed back at 113k and new fluid put in. Around 140k On an on ramp to the highway, it started to "slam" downshift from 3rd to 2nd gear only. Literally feels like someone just wacked the undercarriage with a massive hammer. It shifts and keeps on pulling. Always happens upon acceleration at about 35mph and the throttle is futher than 3/4 of the way to the floor. Trying some different methods of diagnosis, I realized that if I select the 4WD High option and try to do it, it shifts perfect and does not slam at all shifting. If I go back to 4WD Auto, it will slam upon downshift every time just from 3rd to second. Why in 4WD High is it fine, but in auto it's not? Makes me think it's something other than transmission internals. No check engine light, leaks, or OD light flash. Any help guys? Seems to be more prominent when hot as well (operating temp highway)

 

[TestPoint]

I can't speak to the Ford transmission but I had a similar issue with a ZF transmission in a Jaguar. Anytime the transmission control module (TCM) called for an automatic down shift it would slam into the lower gear.

The problem was that the TCM was not releasing the torque converter lock up valve on downshifts effectively shifting without pushing in the clutch. Since the auto down shift mainly occurred under heavy throttle the effect was quite severe. I learned to shift around the problem until I found an used TCM at low cost. In your case the TCM is integrated into the PCM and there is no JY swap available without dealer participation.

If your situation is related to that a dealer reflash of the PCM may be required to address the issue.