Flywheel Replacement; Engine Mountings - GMC G Service Manual

FLYWHEEL REPLACEMENT

H Remove or Disconnect
1. Transmission, flywheel housing, and clutch.
2. Flywheel bolts.
3. Flywheel.
fe H Clean
• Mating surfaces of crankshaft and flywheel. Remove
any burrs.
| y | Inspect
• Flywheel for burning, scoring, warping, and wear.
Replace the flywheel if necessary. Do not machine
the flywheel.
• Flywheel ring gear for worn or broken teeth.
Flywheel Ring Gear Replacement
1. Use a torch to heat the gear around the entire circum­
ference, then drive the gear off the flywheel, using
care not to damage the flywheel.
NOTICE: Never heat starter gear to red heat as
this will change metal structure.
2. Uniformly heat the flywheel gear to temperature
which will expand the gear to permit installation. Tem­
perature must not exceed 200°C (392°F).
3. As soon as the gear has been heated, install on the
flywheel.
H Install or Connect
1. Flywheel.
2. Flywheel bolts.
H O Tighten
• Flywheel bolts to 90 N»m (65 ft. lbs.).
3. Clutch, flywheel housing, and transmission.
7.4 LITER V8 6A5-21

ENGINE MOUNTINGS

NOTICE: Broken or deteriorated mountings can
cause misalignment and eventual destruction of
certain drive train components. When a single
mounting breakage occurs, the remaining
mountings are subjected to abnormally high
stresses.
INSPECTING ENGINE MOUNTINGS
Front Engine Mountings
NOTICE: When raising or supporting the engine
for any reason, do not use a jack under the oil
pan, any sheet metal or crankshaft pulley. Due
to the small clearance between the oil pan and
the oil pump screen, jacking against the oil pan
may cause it to be bent against the pump
screen, resulting in a damaged oil pickup unit.
1. Raise the engine to remove weight from the mount­
ings and to place a slight tension on the rubber cush­
ion. Observe both mountings while raising the engine.
2. Replace the mounting if the following conditions exist:
• Hard rubber surface covered with heat check
cracks.
• Rubber cushion separated from the metal plate
of the mounting.
• Rubber cushion split through the center.
3. If there is movement between a metal plate of the
mounting and its attaching points, lower the engine
and tighten the bolts or nuts attaching the mounting to
the engine, frame, or bracket.
Rear Mountings
1. Push up and pull down on the transmission tailshaft.
Observe the transmission mounting.
2. Replace the mounting if the following conditions exist:
— Mounting bottomed out (tailshaft can be moved
up but not down).
3. If there is relative movement between a metal plate of
the mounting and its attaching point, tighten the bolts
or nuts attaching the mounting to the transmission or
crossmember.
FRONT MOUNTING REPLACEMENT
M Remove or Disconnect (Figures 35, 36, 37,
and 38)
1. Battery negative cable.
NOTICE: When raising or supporting the engine
for any reason, do not use a jack under the oil
pan, any sheet metal or crankshaft pulley. Due
to the small clearance between the oil pan and
the oil pump screen, jacking against the oil pan
may cause it to be bent against the pump
screen, resulting in a damaged oil pickup unit.
• Support the engine with a suitable jack. Do not load
the engine mounting.