A/T - Evaluating Peened Spacer Plates

91chevy24

GMC NUMBER: 91-7A-141

GROUP: 7A Automatic Transmission


DATE: August, 1991


CORPORATE NUMBER: 177120


SUBJECT: EVALUATING PEENED SPACER PLATES - ALL AUTOMATIC TRANSMISSIONS

MODELS: 1982-1991 ALL TRUCKS WITH HYDRA-MATIC AUTOMATIC TRANSMISSIONS

Figure 1:

Some spacer plate peening is considered acceptable and preferred because it can help seat the check-ball. This bulletin will help you decide if a spacer plate needs to be replaced due to a peening condition.

Service Procedure:
The following two procedures can help determine if the spacer plate can be reused. The following must be performed at all check-ball locations.
1. The spacer plate must be inspected 100% for raised material on the opposite side of the check-ball seat (see figure 1). If the material on the opposite side is raised, the peening is too severe and the spacer plate must be replaced.

Figure 2:

2. To verify that the spacer plate is peening evenly and the ball is sealing correctly, seat the check-ball on the spacer plate. Shine a beam of light on the opposite side and inspect for light between the spacer plate and check-ball (see figure 2). No trace of light should be present. If light can be seen, a proper seal does not exist, and the spacer plate must be replaced.

Service Manual Reference:
Refer to the HYDRA-MATIC Automatic Transmission Diagnosis section of your service manual or unit repair manual for proper check-ball locations and functions.