I am performing a couple of transmission rebuilds, I successfully pulled off the jakes rebuild and it is working great. Now I am doing another one with a ck performance recal kit.and was wondering if anybody know what the purpose of checkball #8 does. ATSG manual says it for prnd 4, Jakes shift kit does not use it and the ck shift kit does. I want to give a shout out to Jakes for there customer service.

 

To put it simply...

The #8 check ball closes separator plate hole #33A and forces Third clutch feed oil from the 2-3 shift valve to pass through separator plate orifice hole #33B and on to apply the Third clutch (DIRECT) piston/ clutch pack for third gear shift.

Separator plate orifice hole #33B would be what everyone refers to as the Third feed hole in the separator plate for tuning/ drilling for shift feel.

The actual Oil flow would be:

...2-3 shift valve to the #8 check-ball and the third feed hole to a fork
...One way sends third feed oil to the third accumulator piston pushing against the accumulator oil
...The other way goes to the #11 check-ball bath-tub and closes off the reverse feed side of the circuit, then goes to the third clutch apply piston/ clutch pack.

 

Thanks for the reply. I am quesssing the reason for leaving the checkball out then is too get the direct piston to apply faster and with more firmness.