Chevrolet Silverado / GMC Sierra. Manual - part 837
4. Flush the oil cooler and pipes with water and solution for 2 minutes. During this flush,
attach the shop air supply 825 kPa (120 psi) to the flushing system feed air valve (2) located
on the J 35944-A for 3-5 seconds at the end of every 15-20 second interval to create a
surging action.
5. Release the trigger (8) and turn the J 35944-A water supply valve (1) to the OFF position.
BACK FLUSH
1. Disconnect both hoses from the oil cooler pipes and then connect them to the opposite oil
cooler pipe. This will allow the oil cooler and pipes to be back flushed.
2. Repeat steps 3 and 4 of the INITIAL FLUSH procedure.
3. Release the trigger (8) of the J 35944-A and allow water only to rinse the oil cooler and
pipes for 1 minute.
4. Turn the J 35944-A water supply valve (1) to the OFF position and turn OFF the water
supply at the faucet.
5. Attach the shop air supply to the flushing system feed air valve (2) on the J 35944-A and
blow out the water from the oil cooler and pipes. Continue until no water comes out of the
discharge hose (5).
FLOW CHECK
be captured in a suitable container, preferably with a lid.
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Fig. 7: Connecting Return Pipe, Top Connector, To Discharge Hose
Courtesy of GENERAL MOTORS CORP.
1. Disconnect both hoses from the oil cooler pipes. Connect the oil cooler feed pipe, bottom
connector, to the transmission. Connect the return pipe, top connector, to the discharge hose
(5). This will require the use of J-44835-1 . Clip the discharge hose (5) onto an empty oil
drain container.
2. Confirm the transmission is filled with automatic transmission fluid.
3. Start the engine with the transmission in PARK range and run for 5 seconds at 2,400 RPM.
A minimum of 2.2 L (2.3 quarts) must be discharged during this 5 second run time.
If fluid flow is greater than 2.2 L (2.3 quarts) in 5 seconds at 2,400 RPM, go to step 4.
If fluid flow is less than 2.2 L (2.3 quarts) in 5 seconds at 2,400 RPM, perform the
following diagnosis:
Disconnect the oil cooler feed line at the radiator. Connect the discharge hose (5) to
the cooler feed line. Clip the discharge hose (5) to the empty oil drain container. Start
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
the engine with the transmission in PARK range and run for 5 seconds at 2,400 RPM.
A minimum of 2.2 L (2.3 quarts) must be discharged during this 5 second run time at
2,400 RPM. Do the following according to the flow rate:
Insufficient feed flow: Inspect the transmission.
Sufficient feed flow: Inspect the oil cooler return pipe, the oil cooler located in
the radiator, and the auxiliary oil cooler.
4. Remove the discharge hose (5), connect the cooler feed and return pipes to the transmission
and fill the unit to the proper fluid level. Inspect the transmission oil cooler pipe
connections at the radiator, the auxiliary cooler and the transmission for leaks.
CLEAN-UP
1. Disconnect the water supply hose (7) from the J 35944-A and bleed any remaining air
pressure from the flusher tank (4).
2. Remove the fill cap (9) from the J 35944-A and return any unused flushing solution to its
container. Rinse the J 35944-A with water. Do not store the J 35944-A with flushing
solution in it.
3. After every third use, clean the J 35944-A as described in the instructions included with the
tool.
4. Dispose of any waste water/solution and transmission fluid in accordance with local
regulations.
BUSHING AND MATING SHAFT INSPECTION
Any of the following bushing conditions require replacement of the bushing and/or housing:
Discoloration due to heat distress
Misalignment or displacement of bushing as a result of spinning in housing
Medium to heavy scoring that can be easily detected with fingernail. Light scoring is a
normal condition.
Debris embedded into the bushing lining material
IMPORTANT: Proper bushing and corresponding mating shaft inspection
should be performed before replacing the bushing, shaft, and in
some cases, the component which houses the bushing.
Thoroughly clean and dry the bushing and shaft surfaces before
inspecting for damage.
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Obvious damage, including excessive and uneven wear
Excessive polishing. Minor polishing of the bushing is an indication of normal wear and
does not require replacement.
Any of the following conditions require replacement of the bushing's mating shaft:
Discoloration due to heat distress
Rough surface finish that can be easily detected with finger
Obvious shaft abnormalities, including warping or uneven surfaces
Obvious damage or cracking
EXCESSIVE SLIPPAGE AND CLUTCH CHATTER
Condition
Action
Incorrect speed sensor readings
See speed sensor DTCs.
Incorrect fluid level
Correct the fluid level. Refer to Transmission
Fluid Check.
Main pressure low
Repair the transmission.
TCC clutch not applied
Inspect the torque converter clutch system
wiring, pressure, and controls. Repair as
necessary.
Ranges 1, 2, 3, 4 Only
1-2-3-4 clutch slipping, leaks at rotating
clutch seals, leaks at piston seals, 1-2-3-4
clutch plates worn
Inspect the 1-2-3-4 clutch plates, and piston
and rotating seals. Replace/rebuild as
necessary.
Ranges 4, 5, 6 Only
4-5-6 clutch slipping, leaks at rotating clutch
seals, leaks at piston seals, 4-5-6 clutch
plates worn
Inspect the 4-5-6 clutch plates, and piston and
rotating seals. Replace/rebuild as necessary.
Ranges 3, 5, R Only
3rd, 5th and Reverse clutch slipping, leaks
at piston seals, 3rd, 5th and Reverse clutch
plates worn
Inspect the 3rd, 5th and Reverse clutch plates
and piston seals. Replace/rebuild as necessary.
Range 2, 6 Only
2-6 clutch slipping, leaks at piston seals, 2nd
clutch plates worn
Inspect the 2-6 clutch plates and piston seals.
Replace/rebuild as necessary.
Ranges 1, R Only
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado