904 kickdown servo test

[Gkprice1]

I just rebuilt a 904 transmission. Stock rebuild. Before putting the valve body back in and buttoning it up, did an air pressure test, (about 30 lbs). I hear the clutch packs engage and the rear servo engages strong.

Problem is the front servo. It's blowing air out. I took the spring and top cap (whatever it's called) out and applied air. It blows the piston out of the bore. When there's fluid in there will it make a difference and piston get more pressure behind it?

 

[Xcudame]

You did grease the center shaft/pin and all the sealing rings in the front/kickdown servo, correct? The grease will help it function during the air test. And yes, the fluid is thicker than air.

 

[Gkprice1]

You did grease the center shaft/pin and all the sealing rings in the front/kickdown servo, correct? The grease will help it function during the air test. And yes, the fluid is thicker than air.

I did grease the pin and rings. Actually poured some fluid into the port and tried again. Worked fine until the fluid ran out. I'm sure the new seals will swell when wet with fluid too.

 

[Xcudame]

Fluid makes it work better than air for certain!