K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Fluid Pump: Customer Interest
A/T - Fluid Out Vent Diagnostic Tips
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.
