Chevrolet Silverado / GMC Sierra. Service manual — part 1031

OIL OUT THE VENT

Oil Out the Vent

VIBRATION IN REVERSE AND WHINING NOISE IN PARK

Vibration in Reverse and Whining Noise in Park

RATCHETING NOISE

Ratcheting Noise

TICKING NOISE IN REVERSE

Ratcheting Noise

POPPING NOISE

Checks

Causes

Input Speed Sensor

ISS loose in bore

ISS O-Ring

Damaged or missing

Oil Pump (4)

Chamber in pump body rotor pocket

Miscellaneous

Fluid level-overfilled

Checks

Causes

Oil Pump (4)

Chamber in pump body rotor pocket

Miscellaneous

Fluid level-overfilled

Checks

Causes

Parking Brake Pawl (50-81) The parking pawl return spring is weak, damaged, or

misassembled

Checks

Causes

Parking Brake Pawl (50-81) This noise may be caused by a bent parking lock actuator

assembly (85). A bent actuator may not fully move the pawl
(81) away from the internal reaction gear (684) when in
reverse allowing the pawl to lightly contact the teeth of the
internal reaction gear. The condition my not occur in forward
gears as the additional actuator travel moves the pawl further
from the gear teeth.
To correct this condition, replace the parking lock actuator
assembly (85).

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Popping Noise

WHINE NOISE VARYING WITH RPM OR FLUID PRESSURE

Whine Noise Varying with RPM or Fluid Pressure

BUZZ NOISE OR HIGH FREQUENCY RATTLE SOUND

Buzz Noise or High Frequency Rattle Sound

NOISE IN RANDOM RANGES

Checks

Action

DEFINITION: A popping noise, similar to popcorn popping
Oil Pump System

Check fluid level.

Inspect for pump cavitation, indicated by bubbles in
fluid.

Inspect the transmission fluid filter for a leaky seam.

Inspect the transmission fluid filter seal for improper
positioning or for a cut seal.

Checks

Action

DEFINITION: In all ranges, a whine which may be sensitive to RPM load, or which ceases
when the TCC engages, or which is sensitive to the oil pressure
Torque Converter (1)

Verify that the noise is internal to the torque converter by
placing your left foot on the brake with the gear or selector in
Drive. Momentarily stall the engine. Torque Converter noise
increases under load.

Oil Pump System

Verify that the noise is internal to the oil pump during a
preliminary oil pressure check. An increase in line pressure
will vary an oil pump noise.

Checks

Action

DEFINITION: A buzz or high frequency rattle

Trace Cooler Pipes

Check for binding or
contact at the Radiator,
other than at the Cooler
Pipe connectors

Verify a pressure buzz by watching for a needle vibration of
the pressure gage. A road test may be necessary. Refer to
Road Test.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Noise in Random Ranges

NO DRIVE IN ALL RANGES

No Drive in All Ranges

NO DRIVE IN DRIVE RANGE

SHIFT LEVER INDICATES WRONG GEAR

Checks

Action

DEFINITION: Noise only in certain gear ranges
Refer to Range Reference . Determine the power flow and the applicable components that
may be causing this noise.

Checks

Causes

Low Transmission Fluid
Level

Transmission or cooler line leak

Oil Pump (4)

Damaged oil pump rotor (212)

Torque Converter (1)

The converter is not bolted to flex plate

Damaged pump drive

The stator roller clutch is not holding

Checks

Causes

Oil Pump (4)

Damaged vanes

Missing slide spring

Oil pump screen assembly plugged or damaged

Oil pump rotor guide omitted or misassembled

Oil pump rotor cracked or broken

Porosity in fluid pump

Oil pump surfaces not flat

Excessive oil pump rotor clearance

Forward Sprag Clutch
Assembly (642)

Damaged sprag

Worn or pitted inner race

Input (662) and Reaction
(681) Carrier

Damaged or worn gears

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Shift Lever Indicates Wrong Gear

NO GEAR SELECTION

No Gear Selection

ENGINE STARTS IN GEAR

Engine Starts in Gear

DELAY IN DRIVE AND REVERSE

Delay in Drive and Reverse

Checks

Causes

Manual Valve (340)

Not engaged to detent lever

Detent Roller Pin (63)

Missing or damaged

Detent Roller (63)

Broken or disconnected

Detent Spring (63)

Broken or disconnected

Manual Valve Link (89)

Loose or missing

Manual Shaft (84)

Flats not parallel

Indicator Linkage

Misadjusted

Checks

Causes

Detent Lever (63)

Nut loose or missing

Manual Valve (84)

Stuck

Spacer Plate/Gaskets (47,
48, 52)

Blocked holes

Control Valve Body to Case
(60/103)

Blocked channels

Checks

Causes

Manual Valve (24)

Not engaged to detent lever

Transmission Range Switch Not working or mispositioned

Checks

Causes

Forward Clutch Piston (630) Cut or damaged piston seals
Low and Reverse Clutch
Piston (695)

Cut or damaged inner, outer or center clutch seals

Reverse Input Clutch Piston
Assembly (607)

Cut or damaged inner or outer clutch seals

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado