U660 DELAY AND BANG INTO FORWARD

[transpck08]

This unit has a 3 second delay and then bangs into forward gear. Other than that, there is no issues at all. Shift flawless and reverse engagement is solid. I did install the sonnax oring end plugs and accumulators as they had signs on wear. Went thru the valve body very good when it was on the bench and no stuck valves whatsoever. Any ideas?

[transpck08]

After looking at some past webinar sheet, looks like im going to have a valve body issue even though i vacuum test all critical bores and they all check at 20-22. I tried the reset and relearn and that didnt help at all.

[dhritsko]

the primary PR valve or bore is the one I see mentioned . also the C1 clutch is coming on , maybe missed something there . The OWC is also holding , is it good ?

[transpck08]

Air tested the c1 drum and it applied at 30psi. Sprag is good and holding. I will try another valve body if not then i might have a c1 piston or drum issue.

[transpck08]

***UPDATE*** Installed different valve body and same thing. Drive excellent but the 3 second harsh delay in forward is whats killing me on this tranny. Im pretty lost here as what could it be. Air tested again the low/rev clutches, c1 & c2 and they're all solid. Cant here a leak

[jb.stp]

Here's the complete circuit...

SL1 (C1) solenoid

drill N-D orf (.050") to .073"

clutch control valve stuck against spring

sequence valve stuck in mid-way position

Leak at c1 accu (not very likely)

gauge c1 pressure tap
(center plug on elevated tri-circuit from center of cover) and observe psi drop on N-D engage (testing for leak in cover or drum)

if bad...
air check C1 clutch thru case (remove VB) to reveal drum/cover/seal ring leaks

[ If you need help finding the N-D orf.. call me 850 545 2146 Dean Mason / TransLab ]

REPLY POSTED BY JIM BROOKSHIRE

[Jaradwarren]

Dont forget to reset trans adapts. Some scan tool do work when doing this. Get to temp and relearn

[transpck08]

Reprogrammed with techstream as the software was out of date. No luck. Gave installing shop bad news that its internal and needs to come down. Ordering new pistons for c1 clutch

[transpck08]

Order new Seal aftermarket hi-per blue piston kit. shop installed the unit and all is working good. Those darn cheap pistons can bite you in the as*

[transpck08]

So this unit is back after 1 week from me changing the bonded pistons again. This time it came in with a U0101 Lost communication with TCM. Tranny was working like a champ. Cleared code and came back after a couple of miles. Would not upshift and code couldnt be cleared. The following day i turn on the car and it has the delay in drive (3 seconds) with a harsh engagement. Electrical guy came and found dirty terminal pins. He cleaned them and erased the code. Drives good but the delay is still there. This unit is really kicking me in the butt. Worked fine for 11 months and now i cant get this thing to work like it should.