S15/T15 2WD Jimmy L4-151 2.5L (1985)
Drive/Propeller Shaft: All Technical Service Bulletins
Driveline - Vibration At 2800 RPM
GMC NUMBER:
91-7B-63
GROUP:
7B Manual Transmission
DATE:
February, 1991
CORPORATE
NUMBER:
067203
SUBJECT:
DRIVELINE MOAN, DRONE, RESONANCE, VIBRATION AT 2800 RPM
MODELS:
1984-86 and 1989-91 S TRUCKS EQUIPPED WITH BORG-WARNER MANUAL TRANSMISSION AND 2.5L ENGINE
Some 1982-86 and 1989-91 S pickup trucks may experience a condition described as driveline moan, drone, resonance or vibration. This condition
usually occurs at approximately 2800 rpm when the cab and/or interior panels may buzz or vibrate.
Service damper kits are available for installation on these S pickup trucks. These dampers will significantly reduce vibrations in the 2800 rpm range.
Refer to the SERVICE PROCEDURE section for the specific action required for the model years listed.
VEHICLES INVOLVED
1984-86 and 1989-91 S pickup trucks (models S10603, S10653, S10803) equipped with 2.5L engine and Borg-Warner 4 or 5 speed manual
transmission.
SERVICE PROCEDURE:
1984-86 S pickup trucks:
These vehicles can be repaired using the damper P/N 14073312 and method described in GMC Truck Service Bulletin 83-B-65 (Corporate Number
836589). This bulletin calls for a transmission mount change on some models. If the transmission mount features the dual captive stud mounting, the
transmission mount does not require replacement.
1989-91 S pickup trucks:
Service damper kit P/N 15674891 containing a damper, new transmission extension housing with damper mounting bosses and fasteners should be
installed.
Figure 1 - Extension Housing Assembly
