Clutch air test

**MontyJ** · 07-21-2012

Does anyone have or know the procedure to air test the clutches in a 4t65e? I built the clutch stack and filled the apply holes with fluid. When I use about 25psi in the apply holes, the input clutch engages fine, and the fourth piston engages fine. Second sounds like it's leaking and does not engage. I actually get air and fluid out of the input apply hole. It also sounds like it's leaking around the shaft. This tranny doesn't have the 4-lobed seals under the 2nd peak seals, and the peak seals are new.

Third also does not engage. It sounds like it's leaking around the shaft, but also puts air and fluid out of the input apply hole. I tried inverting the stack and had the same results. I can't find the actual procedure so I'm not sure if I'm doing it right, or if I have a check ball leaking or what.
The problem with third could be the teflon seals, but they seem to have resized just fine. I can feel the driven sprocket support go over each one as I put it on.

Any help would be greatly appreciated.

**MontyJ** · 07-21-2012

Update:

Took everything apart and double checked everything. I put the 2nd clutch piston into the housing and applied 25psi to the apply hole. The piston moved nicely. Put the spring back in and applied air...nothing. Bumped the pressure up to 45psi and the clutch applied. I did the same thing to 3rd with the same results. I put the entire stack back together and tested all clutches at 45psi. Everything engaged. Does anyone know what the pressure should be?

**Trannyman95** · 07-23-2012

The transmission has much higher line pressure to apply clutches and at 25 or 45 psi you are working more against the return spring pressure than anything and likely just hear leakage. I use full shop air pressure which is set around 100 psi which is still lower than what actual operating pressure is. Make 100% sure everything is assembled and clutches/snap rings are in place! Any air test without the clutches installed is likely going to cause a seal to get clipped or damaged from the piston traveling too far and spring pressure forcing it back down and tearing it.