Contour Enthusiasts Group Archives Forums General Troubleshooting ATX Code 628 -help!

I have a 95 Mystique with 2.5L and CD4E auto. Problem: After a drive where I exceed 100KMs/Hr (We're talking Canadian here! = approx 62mph) the trans shifts very harsh from 1-2, -if I accelerate any faster than a crawl, it nearly pulls the front end out of the car!! The 2-3 and 3-4 shifts aren't as harsh, but stiffer than normal. I get no CEL but my code reader (EECIV) indicates a 628. When I clear the code, the harsh shifting goes away. The wife can putter around for a week and no problem, but when I get in it again, up to highway speed, same thing. I've done a trans flush (opened the cooler return line and bled 8 liters of Mobil1 through it!) -seemed to help smoothness, but still having problem. The trans is a replacement by the previous owner with probably 60-70k Klicks on it.
Anybody know if there's something more I can do before I submit myself to a pistol-whipping by Ford or AAMCO? or just bite the bullet. Thanks in advance for responses.

I would find out who repaired/replaced the original tranny.
Sounds like the pump seal wasn't replaced properly.
The 95 CD4Es were prone to popping pump seals, and they required new seals and a newly designed pump.

If you do opt to get it rebuilt,
have it rebuilt with a TransGo Shift Kit.
It comes with new gaskets that are better than OEM,
and it also comes with a Valve Body Repair kit, to fix your Valve Body as well.
The Valve Bodies on the CD4E wear out prematurely.