low pressure at 727 front clutch

[willard]

I'm rebuilding my tranny. There was a problem with a thump/dalayed engagement of both 3rd and reverse. Something with front clutch - I though warped/broken lip seal. I disassembled the tranny, replaced the front clutch seals, friction discs, sealing rings on the pump extension. Now I assembled the rear and front reatiners (clutches) with the pump on the bench and tested them with compressor set at max 25 psi. Rear clutch engaged fine at approx 15 psi, the front had a leak (there was only 4 psi). When I poured a few drops of ATF to the front clutch slot and a few on the bushing-pump extension joint it was better and the clutch pack applied at 11 psi. There were some bubbles in the atf covering the retainer bushing to pump extension joint.
As I repleced the sealing rings it should not leak there? Also the lip seals were installed properly and piston moved quite freely in the retainer so the seal was nod warped.

I assembled everything in  the case (minus VB) and performed pressure check once again. Therewas no significant difference. Rear clutch firm, front clutch did worked but less firmly.

Is it acceptable or should I seek for a solution. If so what can make pressure escaping?

[Ck[FIN]]

Use teflon sealing rings at the pump/stator support and give it a try. engagement at 11psi sounds pretty good though IMHO.

https://www.coperacingtrans.com/product_info.php?cPath=73&products_id=354&osCsid=c32a8651159568a75a6fbc1376e2f25c

[willard]

thanks for aswer, I'll leave it as is if you say so. this is a stock tranny so no abuse there.

I dont know why, however, I lost the endplay somewhere during reassembly (no spacers were replaced,sungear not removed). I have to recheck the clutch packs thicknesses...

[6packCuda]

I think you're ok if it engages at 11 psi. They usually do leak a little when you air check them. I usually check them at 25-30 psi. I've found that spinning the drum while air checking it makes it seal up better.