Engine Mountings - GMC G Service Manual

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 hot" as
this will change the metallic structure.
2. Uniformly heat the flywheel gear to a temperature
which will expand the gear to permit installation. Tem­
perature must not exceed 204°C (400°F).
3. As soon as the gear has been heated, install on the
flywheel.
H Install or Connect
1. Flywheel.
2. Flywheel bolts.
HO
Tighten
• Flywheel bolts to 100 Nvn (75 ft. lbs.).
3. Clutch, flywheel housing, and transmission. Refer to
TRANSMISSION AND CLUTCH (SEC. 7).

ENGINE MOUNTINGS

NOTICE: Broken or deteriorated mountings can
cause the misalignment and eventual destruc­
tion 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, crankshaft pulley, or any sheet metal. 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.
SMALL BLOCK 6A4-25
Rear Mountings
1. Push up and pull down on the transmission tailshaft.
Observe the transmission mounting.
Replace the mounting if the following conditions exist:
2.
• Rubber cushion separated from the metal plate
of the mounting.
• 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
Remove or Disconnect (Figures 34
B
through 37)
NOTICE: When raising or supporting the engine
for any reason, do not use a jack under the oil
pan, crankshaft pulley, or any sheet metal. 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.
1. Engine mounting through-bolt and nut.
NOTICE: Raise the engine only enough for suffi­
cient clearance. Check for any interference
between the rear of the engine and the dash
panel which could cause distributor housing
damage.
• Raise the engine only enough to permit removal of
the engine mounting.
Mounting assembly bolts, nuts, and washers.
2.
3. Mounting assembly.
B Install or Connect (Figures 34 through 37)
1. Mounting assembly.
NOTICE: See " Notice" on page 6A4-1 of this
section.
Mounting assembly bolts, nuts, and washers.
2.
HO
Tighten
• Fasteners to specifications. Refer to figures 34
through 37.
3. Engine mount through-bolt and nut. Lower the engine
until the bolt can be inserted. Install the nut.
HO
Tighten
• Through-bolt nut to specifications. Refer to fig­
ures 34 through 37.