Auto Trans Rebuild Chapter 8 Air Check

Before the valve body is installed, Kyle explains how to check the hydraulic integrity of each clutch pack

[leifer]

FYI anyone who comes across this, replacing solenoids solved my problem, so far. I had slip on 4-5 upshift, jolt on 5-6, and 2-1 downshift bump. Codes came up 4f8A and also 4f86 for 4-5 upshift but no other codes. Originally i just attempted with the bridge and finger seals, but that did not solve the problem. I have been able to test the car on at least one road trip and a few high load shifts, and so far so good. If anyone buys a car with a higher mileage ZF automatic transmission (over 120k miles, 200k km) at the first sign of transmission issues I would recommend this service.

[leifer]

when doing this are there any special precautions to take regarding pumping air in to these passageways?

[jtp]

how much air pressure do you use? I am building a TH350 and have positive, full piston travel with 25 psi, but I can hear very slight air passing past piston seals. in particular the piston on the front pump bench checked fully extends with air, but I can see it slowly bleed back down once I stop feeding it air, but still holding the air nozzle tight against the air feed hole in the pump. I read that this can be normal since the piston isnt actually pushing against any clutches.. Is this ok?