• Register Today It's free! This box and some ads will disappear once registered!

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. ;)