S15/T15 2WD P/U V6-173 2.8L VIN B 2-bbl (1983)
Flex Plate: Technical Service Bulletins
A/T Flexplate - Clicking/Knocking Noise
GMC NUMBER:
87-T-90
GROUP:
6-Engine Diagnosis
DATE:
October, 1987
CORPORATE
NUMBER:
736106R
SUBJECT:
AUTOMATIC TRANSMISSION FLEXPLATE REPAIR
MODELS:
ALL 1983-1987 S/T TRUCKS EQUIPPED WITH 2.8L (VIN CODES B AND R) ENGINES AND AUTOMATIC TRANSMISSIONS
Some 1983-87 S/T trucks equipped with a 2.8L V-6 engine and an automatic transmission may exhibit a noise comparable to an engine click or knock at
the REAR of the engine. This condition may be due to a cracked flexplate assembly. If this condition is encountered, perform the following inspection
and repair procedure as necessary.
1.
Remove flywheel cover. Remove bolts attaching transmission torque converter to flexplate. Slide converter away from flexplate. Inspect flexplate
to crankshaft mounting and torque converter bolt attaching areas for cracks. If cracks are evident, a transmission misalignment has occurred.
Proceed to step 2.
FIGURE NO. 1
2.
Remove the transmission from the engine using the procedures in Section 7A-Automatic Transmission of the S/T Service Manual. Remove and
replace the flexplate and perform the following procedure to insure that the root cause of the condition is eliminated.
A.
Both 15.0 mm (0.590") long transmission case dowel pins, located in the rear of the engine cylinder and case assembly must be removed and
replaced with two 19.0 mm (0.748") long dowel pins, P/N 477231. Pin removal can be accomplished with the use of an "easy-out" and large
tee handle or other similar method. Care should be exercised to avoid damage/deformation to the precision machined locating counterbores in
the cylinder case (block). Particular care should be taken to avoid cracking the cylinder case (block). Install the pins to a depth that provides
8.8 mm (0.35") protrusion, as shown in Figure No. 1.
