Need help with diag. 5r55e | Ford Explorer Forums - Serious Explorations

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Need help with diag. 5r55e


Active Member
October 5, 2009
Reaction score
City, State
Burnsville, NC
Year, Model & Trim Level
1999 Ford Explorer V8 AWD
Hi I'm new to these forums. I have a '97 Explorer XLT 4x4 with the famous 5r55e and had it rebuild at a local transmission shop. The original trans was rebuild twice while in the shop because they couldn't get it to shift right. They pulled it apart a second time and rebuilt again and still didn't shift right. They ordered another unit and rebuilt it and still didn't shift right and they pulled it apart and rebuilt it again. :mad: 2 1/2 weeks later I get it back and still not right. Don't worry I paid nothing because they didn't fix anything.

The symptoms, 3-4 shift lags, revs between shift and sometimes soft shift. OD seems to slip a little sometimes after TC is locked (not all the time). An occasional lag with 2-3 shift and a rev between shift. Now I'm pretty sure that the hard parts are good and the clutches, bands and plates are probably replaced because the shift is great when it works right. Does this sound like a problem with the EPC solenoid, valves or computer??? I've read alot of the posts on this forum site and it looks more like EPC solenoid and/or the boost valve. Should I go ahead and replace the EPC and install the Sonnax valve kit, or before I go to the valve body look towards the computer??? I'm lost on this one. I can rebuild and diagnose AODs and AODe transmissions but this is a tough one for me.