Ford C6 revs in 2nd and really bad in third

Recent rebuild with few miles. Been sitting in the shop for the last year or so. Was behind a healthy 472. Now behind an even more healthy 552. I would say 600 hp to 800 hp with the engine change. Anyway, tranny worked great with the 472. Car sat while the 552 was built. Now the thing revs in second and is almost like in neutral in third. Thought is was the converter. Took it out and drove down to PTC. They rebuilt it for this motor and said, "this one will work", "you won't blow through this one".

Fluid level is good(Mercon III) and the shift detents on the shifter are perfect on the shift linkage. First and reverse work great but car revs in second and really revs in third.

It is a reverse manual valve body and I have no idea who's v.b. it is. My tranny guy who knows Fords had never seen one before. Again, it worked great behind the 472 but something is way off with the 552.

Any suggestions? Thanks in advance.

Frank

Did you go through the valve body and clean it out and check for sticking valves? How did the fluid look, and was anything in the bottom of the pan?

Nothing in the pan. Fluid is new and still looks and smells new. No, I haven't touched the v.b. since it was built.

Did you give Frank Merkel a call? Hopefully he comes by here and can help you. It kind of sounds like slipping clutchs in the forward and high drums, but with the pan clean, that does not add up.

Talked with Frank today. Asked about installing his v.b. and he was very helpful. Regarding my problem with 2nd and 3rd. Not so much.

I was at the race track and my crystal ball doesn't work well at long distance ! LOL
Frank

It was obvious you were busy. I will try your v.b. on Thursday when I get back in town. I need to know the band adjustment setting.

So frustrated at this point. Supposed to run Dragweek this year. Missed last year and it's starting to look like I'm going to miss this year as well.

Thanks in advance for anything else I should check.

Frank W.

You could air check you pistons while the valve body is off. Look at the condition of the surface of the high drum were the band rides. Band adjustment is 10 inch pound tight, backoff 1 1/2 turns for a factory trans. Frank may recommend something else on his deals. You might want to take some line pressure reading also if you can. Hope you get it lined out for Drag Week.

band is 120 in/lbs and 1 1/2 turns out , and use a torque wrench! before installing the VB air pressure check the trans to make sure the clutches will apply
Frank

Thanks!

I would put a oil psi gauge on it and run it through the gears and see where it is on the oil psi .

And do the band adjustment as Frank has specified. Good luck