A/T - Erratic or No Upshift
88pontiac02Bulletin Number: 88-7-20
Reference Number: 877123
Publish Date: 3/88
Subject: ERRATIC OR NO UPSHIFT - SERVICE AND PARTS INFORMATION FOR A NEW GOVERNOR DRIVEN GEAR
Models
Affected: 1982 THROUGH 1988 THM 700-R4 (MD8) FIREBIRD AND PARISIENNE VEHICLES
FIGURE 1 - THM 700-R4 TRANSMISSION IDENTIFICATION INFORMATION:
BULLETIN COVERS:
A THM 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 2) may be caused by nicks and/or burrs 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 burrs are found..
FIGURE 2 - "APPLECORED" GOVERNOR DRIVEN GEAR:
DATE OF PRODUCTION CHANGE: (Figure 1)
Beginning July 06, 1987 (Julian Date 187) all THM 700-R4 transmissions were produced with the new governor driven gear.
SERVICE ACTION:
When servicing any THM 700-R4 governor driven gear for an "applecored" condition, use the new governor driven gear and pin package listed under "Service Parts Information". NOTE: The new THM 700-R4 governor gear is green in color (the previous gear was blue.) This can be used as another method of identification.
When servicing any 1982 through 1986 THM 700-R4 governor driven gear for conditions other than applecoring, the previous governor driven gear, package number 8642928, should be used until current service stock is depleted.
SERVICE PARTS INFORMATION:
Part No. Description
8663995 THM 700-R4 - Governor Drive Gear and Pin Package
SERVICE MANUAL REFERENCE:
Refer to the appropriate 1988 Unit Repair Service Manual sections for removal and installation procedures not covered in this bulletin.