A/T - 200, 325, 2004R, 3254L GM Servos

TRANSMISSION: 200, 325, 200-4R, 325-4L

BULLETIN: # 016

SUBJECT: GM Servos

DATE: July 1990

GM Servos

USE A LARGER APPLY AREA

Complaints of 1-2 slide, 1-2 bump, soft 2-3, 2-3 flare or 3-2 flare in a 79 or later 200, 325, 200-4R or 325-4L can often be corrected by installing a servo with a larger apply area. The apply area is the part of the servo that rides in the servo cover. The larger the apply area, the more force with which the servo will apply.

The servo will also release slower during the 2-3 shift. To determine the size of the servo, check the last 3 digits of the servo cover casting number. The following chart lists the last 3 digits with the apply area size.

WATCH THESE POINTS

Please note, when using the "569" servo we recommend not to install the servo release spring. Also note the brackets around 141/692 and 694/145. The brackets mean that these servo's are the same size and changing from one to the other will have no affect. For example changing from a 141 to a 692 won't do anything, you need a 694 or 145. Usually going up 1 size is sufficient to correct most servo complaints. You may want to save 144 servo's for heavy duty applications. It is also VERY important to check and set the proper servo travel. 1/16" to 1/8" is the best servo clearence to avoid shift quality complaints. Either change servo pins or use shims to obtain the recommended clearence.

FOR ADDITIONAL INFORMATION:

Refer To:
ATRA TSB 95-6
ATRA TSB 86-36
ATRA TSB 86-20

BULLETIN RECAP

^ Set proper servo travel to 1/16 to 1/8 during rebuild.

^ If using "569" servo, leave out the return spring.

^ If you still have a shift quality complaint, use a larger servo.