Automatic Transmission - GMC T Series 1994 Repair Manual

19. FLYWHEEL
73. BOLT
75. CAP, CRANKSHAFT BEARING
76. BEARING, CRANKSHAFT
77. BEARING, CRANKSHAFT THRUST
Figure 31— Crankshaft and Components
CLEANING, INSPECTION, AND REPAIR
You will need a solvent tank, large enough to hold the
larger engine parts, along with various bristle brushes
and a gasket scraper. A source of compressed air will
be helpful in the cleaning operations.
Precision measuring tools will be required for the
inspection procedure. These include: micrometers, cyl­
inder bore gage, feeler gages, dial indicator set, etc.
The inspection work, performed with the proper method
and tools, is most important. The rebuilt engine cannot
be expected to perform properly if parts worn beyond
acceptable limits are reused.
BLOCK
The 6.5L uses a pipe plug to block the turbocharger
oil supply. On manual transmission applications a valley
drain tube is used at the rear of the block. This drain
tube prevents fuel or oil that has collected in the valley
from draining onto the clutch and flywheel. Engines
equipped with automatic transmissions do not use a
drain tube.
OIL FILTER BYPASS VALVE AND BLOCK PLUG
REMOVAL
<--► Remove or Disconnect
1. Block drain (if used).
2« Expansion plugs and block heater.
3. Oil galley plugs.
CRANKSHAFT
83. CRANKSHAFT
B8070
4. Oil filter bypass valve. Pry out with screwdriver.
A. Center punch the cup plug leaving 3.2 mm (1/8
inch) hole.
B. Install a 4.8 mm (3/16 inch) sheet metal screw
into hole in cup plug.
C. Using two heel bars pry out cup plug.
D. Using a slide hammer remove oil cooler bypass
valve.
5. Oil cooler bypass valve.
Clean
1. Block in solvent.
2. Block gasket surfaces.
3. Cylinder bores.
4. Oil galleries and passages (figure 32).
5. Scale deposits from the coolant passages.
Inspect
1. Hydraulic lifter bores for deep scratches and var­
nish deposits.
2. Block for cracks.
• Cylinder walls.
• Coolant jackets.
• Main bearing webs.
• Engine mount bosses.