Skylark V6-173 2.8L VIN X 2-bbl (1984)
Flex Plate: Technical Service Bulletins
A/T - Cracked Flex Plate
SIL 88-22 (May)
SUBJECT: GM 2.8L ENGINE
PROBLEM:
Cracking flexplate on vehicles equipped with 2.8L engine and automatic transmission
SOLUTION:
Remove and replace the flexplate, and perform the following procedure to insure that the root cause of the condition is eliminated.
1.
Both 15.0 mm (.590") long transmission case dowel pins, located in the rear of the engine block must be removed and replaced with two 19.0 mm
(.748") long dowel pins, part number 477231. Care should be exercised to avoid damage or cracking to the precision-machined locating
counterbores in the engine block. Install the dowel pins to a depth that allows half the pin to be located in the engine block counterbore, and the
other half to be located in the transmission case.
2.
Inspect the torque converter pilot for wear. The amount of wear can be determined by measuring the outside pilot diameter at a minimum of three
different places around the converter pilot. If the diameter measures less than 20.82 mm (.820") at any location, then torque converter pilot wear
has occurred and converter replacement is required.
3.
Inspect the crankshaft pilot for wear, particularly where the torque converter pilot is supported. If the crankshaft pilot is worn on one side only,
rotate the crankshaft until the worn area is at 12:00 o'clock to allow the torque converter to rest against the unworn area when tightening the first
flywheel to torque converter bolt.
4.
Remove and disassemble the transmission pump assembly. Inspect the pump body bushing for excessive wear or evidence of movement within the
pump body. Replace the oil pump body bushing, or the pump body if necessary.
5.
Inspect the transmission case for deformation in both locating counterbores. Repair any deformation by lightly filing or scraping the counterbores
to insure proper engagement of the engine block locating pins. The transmission counterbores are precision locating holes. Excessive metal
removal will result in engine-transmission misalignment, and repeated flexplate cracking. If counterbore deformation is excessive and cannot be
