Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Technical Service Bulletin # 8649
Date: 860301
All THM Transmission/Transaxle Assembliescontrol Valve Assembly
Number:
86-49
Section:
7C
Date:
MAR., 1996
Subject:
ALL THM TRANSMISSION/TRANSAXLE ASSEMBLIESCONTROL VALVE ASSEMBLY CLEANING/SERVICING
PROCEDURES
Model and Year:
ALL MODELS WITH THM TRANSMISSIONS
TO:
ALL CHEVROLET DEALERS
GENERAL CONTROL VALVE ASSEMBLY CLEANING/SERVICING PROCEDURE
The following information is provided as a recommended procedure for cleaning/servicing all automatic transmission/transaxle
control valve assemblies when:
^
Diagnosis indicates a stuck or sticking valve(s).
^
A Transmission/transaxle pump or torque converter malfunction requires a complete unit overhaul.
EQUIPMENT AND WORK AREA
WORKBENCH
^
Must be clean and free of any foreign material (dirt, grease or other contaminants).
^
Work area should be large enough to allow for the disassembly of the control valve assembly and the layout of each valve
train.
TOOLS
^
Should be cleaned with solvent before and during the disassembly procedures to ensure they are free of any grease or dirt
that may contaminate the control valve assembly.
SOLVENT AND PARTS CLEANING TANK
^
Must be clean and free of contamination from engine or other components.
^
Must be cleaned and filtered if solvent is recirculated.
SAFETY EQUIPMENT
^
Safety glasses and rubber gloves are the minimum requirements to ensure personal safety.
Cleaning Procedures
Tools Required
-
Appropriate Service Manual
-
Awl
-
Micro fine lapping compound
-
Tapered #49 drill bit
-
Pencil type magnet
-
Small flat blade screwdriver
-
Small non-abrasive parts cleaning brush
Cleaning And Disassembly
1.
Remove the control valve assembly from the transmission/transaxle following the procedures contained in the appropriate Service Manual.
2.
Inspect the attaching bolts and bolt holes. Remove metal chips or foreign material that may be present.
3.
Place the control valve assembly in a clean tank and with clean solvent thoroughly wash the entire outer surfaces of the valve body.
4.
Remove the control valve assembly from the solvent and dry it using compressed air.
