Fleetwood Brougham V8-307 5.0L (1989)
Torque Converter: Technical Service Bulletins
Engine - Vibration or Shudder At 800 RPM
Bulletin No.
T-89-89
File in Group
6A
Number
104
Corp. Ref. No.
916103
Date
March, 1989
SUBJECT:
ENGINE VIBRATION OR SHUDDER AT 800 RPM
MODELS AFFECTED: 1986-1989 BROUGHAMS
Some Cadillac Broughams equipped with a 5.0L engine and 200 4R transmission may exhibit an engine vibration or shudder condition at off idle engine
speeds of approximately 800 rpm due to an improperly piloted transmission torque converter. This condition might also feel like an erratic engine miss.
Improper piloting of the torque converter to the engine crankshaft may occur due to improper assembly, metal burrs on either the torque converter hub or
crankshaft pilot hole, or due to excess grease in the crankshaft pilot hole.
When diagnosing this condition:
1.
Remove the bolts that retain the torque converter to the engine flexplate (flywheel).
2.
Move the torque converter fully rearward away from the engine.
3.
Run the engine to determine if the condition is eliminated.
If the condition is gone, torque converter imbalance or improper piloting may be indicated. Inspect the torque converter for damage or missing balance
weights. If the torque converter is damaged or balance weights are missing, replace the torque converter.
If no damage or missing weights are noted, reposition the torque converter back into its proper installed position. Due to part tolerances, it may be
necessary to use two small pry bars between the transmission case and the torque converter to lightly lift and "walk" the torque converter into place.
The engine flexplate should contact the torque converter evenly at all three bolt lug positions. If the flexplate does not make even contact with all three
lugs, then the flexplate is bent as a result of improper piloting and should be replaced. If the torque converter cannot move forward enough to contact the
flexplate, there may be metal burrs or excess grease present in the crankshaft pilot hole. It will be necessary to remove the transmission to perform the
appropriate repair. If the torque converter installs properly and no evidence of a bent or damaged flexplate exists, an out of balance torque converter may
be present. Diagnose as follows:
1.
Change position of converter to flexplate 120~ at a time to cancel out engine and converter unbalance. Recheck in each position for vibration
improvements.
2.
If the vibration condition still exists, leave the torque converter/flexplate in the best balanced position. Install a longer torque converter to flexplate
bolt with washers as needed in each position, one at a time, until the best balance is achieved.
IMPORTANT: Be sure the bolts are not bottoming in the holes. Always rotate the converter by hand after adding washers to ensure proper
clearance.
3.
If the vibration condition still exists, replace the torque converter.
