Tranny still slipping after replacement

[YovannyRamirez]

So it all started off when i blew my tranny cooler coming up a mountain. All of the tranny fluid moved up to the radiator. I replaced radiator and flushed out coolant and added fresh tranny fluid. Ran good for a week or two, shortly after, tranny started to slip coming into 2nd gear and also if i put drive (D) on a hill it will not kick in at all.
Replaced transmission, seal, and filter (got it off a yard of a truck that was rear ended, no shaft or chassis damage). Got tranny up and running runs good. However, i am still having the same slippage but now instead of 2nd gear it is doing it on 3rd gear. it feels like i lose acceleration for a split second and the truck slams itself into 3rd gear. The shifter takes all the gears fine but when i am driving it shifts really rough into 3rd. the fluid on this new tranny is clear and red no metal shavings or anything, and smells good. ????????????

P.S- i added 1 qt of TransX and it worked for a few hours, The next day i added some transmission fluid Lucas and it did not help at all.

Torque converter???

2000 Ford Explorer 4.0 V6 SOHC auto trans

 

[Dave 1955]

Nope..doubt it is the TC.
Do the r's jump much before it actually goes into 3rd?

 

[YovannyRamirez]

No they don't. It just feels like it doesn't accept 3rd gear for like 2 seconds and then when it takes it I feel the gear slam into place. My o/d light is not on (and it works) and I have no other problem with any other gears.

 

[drdoom]

You need to do a run-up on the valve body. But before that I believe I'd get it on a good scanner. Also check to see if you can get a re-flash.

 

[bill06447]

Sounds to me like a powertrain control module issue (or whatever Ford calls it) Multitudes of Chrysler transmissions were replaced in the 90s due to a faulty $80 computer chip

Bill