Direct drive powerglide slipping in high

[superstock50]

Anyone have any ideas? Rebuild with new clutches, steels, seals, gaskets and o-rings. Took the pump apart and inspected. Opened up the valvebody and cleaned. Took the valves out and cleaned/inspected. I've had this thing in and out of the car 4 times in 2 weeks and now I'm at a loss!!

[hpontap]

Are you running the bleeder type valve body in it or a (not a nice word)(not a nice word)(not a nice word)(not a nice word)pit valve ? It could be the jets are too big not allowing enough pressure to fully engage the clutches, pump worn not producing enough pressure, cracked valve body, etc.
Sounds like it is losing fluid pressure to the clutch drum.

[superstock50]

Bleeder type without jets, Phipps valvebody. I have replaced everything but the valvebody and case. Maybe that's the problem. Thanks.

[hpontap]

Check the pressure . Should have between 205 - 215 PSI with a stock pump. 250-255 with aftermarket or shimmed pump.
Check the seal on the input shaft really good. The case could be cracked under the valve body or cracked valve body.
Thats about all I can think of if it was put together right. Good luck with it.

[hpontap]

Did you find the problem with it?

[superstock50]

No, not yet. Tried another valvebody, closely inspected case and did an air pressure test for the servo and high clutch drum. Both were working fine. Pressure test not possible, cooling ports are permanently plugged. Pulling trans today to replace front pump. 😡😡