A/T - Fluid Out Vent Diagnostic Tips

9217chevy03

GMC NUMBER: 90-7A-128

GROUP: 7A Automatic Transmission

DATE: September, 1991

CORPORATE
NUMBER: 177121


SUBJECT:
FLUID OUT VENT - DIAGNOSTIC TIPS (SERVICE INFORMATION)

MODELS:
1982 - 1990 C/K AND R/V/G/P WITH HYDRA-MATIC 3L80 TRANSMISSIONS


Some diagnostic information to consider if fluid is leaking out the vent:

^ Inverted pump gasket or pump gasket off location

- Use alignment pins.

^ Flatness specification of pump body and cover

- Free from burrs.

^ Pump passages clear from chips

- Visual inspection.


^ Overfilled transmission - fluid

- Check fluid level at transmission operation temperature.

^ Pressure regulator pin hole too shallow causing pump face interference. Refer to section 7 of the appropriate service manual for repair procedures. Refer to Truck Service Bulletin 90-7A-118 (Corp No. 067107) for a new fluid level indicator and model application.