48RE rear servo pressure

[Joesixpack]

Doing some pressure tests before I pull the trans and with full tv free rolling on the dyno at 1600 the rear servo pressure is just about 400psi.

Is that a function of running higher line pressure? Line maxes out at about 180 or so.

Pressure tests mostly good, except for a pretty good pressure differential between line and the front servo. Just before the kickdown there's 25 psi less at the servo.

 

[raychem]

I am used to seeing 225-300 @88-95 line pressure. Rear servo/reverse line pressure is proportional to base line pressure. That would explain why you are seeing 400 psi with 180 base line pressure. Be careful as the rear servo may crack in the bore. Upgrade the rear servo as a preventative.

Also, the line pressure fall is normal depending on what is going on between gear shifts. At the front servo, all you can really see is 3rd gear app psi and TQ lock up pressure.