Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Governor: Customer Interest
A/T - Erratic or No Upshift (New Governor Driven Gear)
GMC NUMBER:
88-T-99
GROUP:
7A - Automatic Transmission
DATE:
March, 1988
CORPORATE
NUMBER:
877123
SUBJECT:
ERRATIC OR NO UPSHIFT (NEW GOVERNOR DRIVEN GEAR)
MODELS:
1978-1988 L/D VEHICLES EQUIPPED WITH THM 400/475 (M40/M41) AUTOMATIC TRANSMISSION 1982-1988 L/D VEHICLES
EQUIPPED WITH THM 700 R4 (MD8) AUTOMATIC TRANSMISSION
FIGURE 1 - "APPLECORED" GOVERNOR DRIVEN GEAR
BULLETIN COVERS:
A THM 400/475 or 700-R4 transmission with an erratic or no upshift condition which may be due to applecoring of the governor driven gear.
"Applecoring" of the governor driven gear (refer to Figure No. 1) may be caused by nicks and/or buffs on the governor drive gear. The new governor
driven gear has a higher fiberglass content. Also, inspect the output shaft for nicks and/or burrs on the governor drive gear. Replace the output shaft if
nicks and/or buffs are found.
