An interesting 5R55E Valve Body story | Ford Explorer Forums - Serious Explorations

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An interesting 5R55E Valve Body story


EF Tranny Guru
Moderator Emeritus
February 8, 2003
Reaction score
City, State
Sacramento, CA 95827
Year, Model & Trim Level
1992 XLT
Ok, well maybe not interesting to everyone, but I think it may further our collective knowledge for those interersted.

Some of you know I rebuild VB's for folks that either don't want to DIY, or just don't have the time or resources. I have done around a dozen or so, and am pretty comfortable with the 5R55 VB.

I recently built one for a nice guy in the East Coast, and when he installed it, he had problems. A CEL would come on and the computer would go into FMEM mode. He ended up getting a scanner and found a proprietary code of 1780. He also got a 0743 code. (this is from memory but I think that's right.)

He had installed the pressure riser, and was concrned that may be his problem, so he removed it, in fact I think that was when the 0743 showed up.
We then suspected the harness.

I send him a trans tester and a new harness. Things seemed to check out ok, but the 1780 persisted.

I had a brand new 5R55 VB sitting around, so I put the Superior kit in it (The FORD mod came installed) drilled a new sep plate and sent it out to him (NO ONE fails is my credo). Result. Success.

I was really mystified, and then I read an article in the current issue of ATRA's GEARS magazine. It could have been written about THIS situation!
The article is here:

What I learned is that I may, from this point forward, use the Sonnax fix to the TCC modulator (that is the bore that is such a PITA to remove the little plug from). Sonnax has a reamer that oversizes the bore and adds a sleeve and new valve. Pricey but maybe a good idea.

Morals? Everyone, even someone knowledgeable, has problems from time to time. :eek: And, the TCC is a problem child in the 5R55 VB. :thumbdwn: OH, and, persistence pays off. ;)