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Rexcars27
Rexcars27, Service and Parts Director
Category: Car
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Experience:  26 years in the automotive service and parts industry
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I have an olds bravada 2002 vintage thet the four wheel drive

Resolved Question:

I have an olds bravada 2002 vintage thet the four wheel drive is locked in any suggestions to get it out.
Submitted: 5 years ago.
Category: Car
Expert:  Rexcars27 replied 5 years ago.

HiCustomer I show the Bravada as being an AWD vehicle. This means that all wheels are always engaged. Do you have a switch on the dash to select between 2WD and 4WD?

 

Rex

Customer: replied 5 years ago.
NO SWITCH ON THE DASH
Expert:  Rexcars27 replied 5 years ago.

The Bravada comes in a 2WD version and an AWD version. There is no way to disengage the front wheels in the AWD version.

 

Rex

Customer: replied 5 years ago.
The problem is when I make a sharp turn the front wheels don't freewheel and the vehicle hops because there is no slippage in the tires from front to back.
Expert:  Rexcars27 replied 5 years ago.

Okay, there is a GM bellutin that addresses your issue. Becuase it is a bulletin and not a recall, teh dealer is nto obligated to repair it under warranty.---Rex

 

#02-04-21-008A: Shudder, Rocking Motion, Binding, Feels Like Vehicle is Stuck in 4WD (Crow Hop) When Turning at Low Speeds (Replace Transfer Case Encoder Sensor and Reprogram TCCM) - (Feb 13, 2003)

Subject:Shudder, Rocking Motion, Binding, Feels Like Vehicle is Stuck in 4WD (Crow Hop) When Turning at Low Speeds (Replace Transfer Case Encoder Sensor and Reprogram TCCM)

Models:2002-2003 Chevrolet TrailBlazer
2002-2003 GMC Envoy
2002-2003 Oldsmobile Bravada

 

Condition

Some customers may comment that when turning, the vehicle feels like it is binding, or the vehicle feels like it is stuck in 4WD (crow hop), or that the 4WD system is not working correctly. A shudder type sensation is felt.

Technician Diagnosis

This intermittent condition may be difficult to duplicate. The potential is there at all times for the Bravada. The potential is only present in the Auto Mode of the transfer case with the TrailBlazer or Envoy.

Correction

Important: It is extremely important to check all of the tires before repairs are attempted for these types of customer concerns. Mismatched tires may cause these type of customer concerns. Inspect the tires in the following areas:

Ensure that the tires are inflated to the recommended tire pressure as listed on the tire placard on the driver's door.
Use a tire tread depth gauge to determine the tread depth. The tire tread depth must be nearly equal on all four corners of the vehicle.
Ensure that the tires are all the same brand, size, and tread design.

 

Important: Pay particular attention so that the proper parts are replaced. The parts terminology is somewhat confusing. You will be replacing the encoder (sensor) and gasket not the complete motor assembly.

Currently, the General Motors Parts Catalog lists the following names:

 

Motor Asm, Trfer Case Encoder (This is the Encoder (Sensor). It looks like a donut with three (3) contacts on one side).
Gasket.
Actuator Asm, Trfer Case Four Whl Drv (This is the complete motor assembly consisting of the Motor and housing, the Motor Asm, the Trfer Case Encoder (Sensor), and the gasket).

 

Use the following procedure to replace the Motor Asm, Trfer Case Encoder (Sensor) and Gasket.

  1. If the vehicle is a TrailBlazer or Envoy, place the 4WD selector switch in the 2 HI position.
  2. Raise the vehicle.
  3. Disconnect the wiring harness connector at the top of the transfer case.
    Object Number: 743564  Size: SH

  4. Remove the Actuator Asm, Trfer Case Four Whl Drv. (Motor) mounting bolts.
  5. Remove the motor from the transfer case and set aside.
    Object Number: 660282  Size: SH

  6. Position an oil drain container into position under the transfer case drain plug. Remove the drain plug and allow the transfer case to drain.
  7. Position the motor on a work bench and you will see four retaining tabs that retain the gasket to the motor. Release the tabs to allow removal and discard the gasket.

    Important: Gently lift and tilt the sensor toward the wiring connector wiring to disconnect it. You will notice the two wires to the motor. The red and black wires go to an internal connector within the motor housing. The black plastic connector for these wires does not have a locking tab and is easily disturbed.

  8. Lift/pry the sensor from the motor shaft. Disconnect the sensor from the wiring harness.

    Important: Look at the motor where you just removed the sensor. You will notice the "Hex" in the casting where the new sensor will seat when properly installed.

  9. Connect the wiring harness to the sensor.
  10. Gently insert a suitable tool along side the red and black wires and press down on the black plastic connector to ensure the connector is in the proper position.
  11. Properly align the key way of the sensor on the shaft and install the sensor. Ensure that the hex on the sensor fits in the hex of the casting.
  12. Install the new gasket assembly.
    Object Number:(NNN) NNN-NNNN Size: MH

  13. Inspect the positioning of the gasket and the motor shaft. If necessary to align them as shown, perform the following steps.
    Connect a fused jumper to the transfer case encoder motor connector red wire and the other end to a positive battery terminal.
    Connect another jumper to the transfer case encoder motor connector black wire and momentarily touch the other end of this wire to the ground terminal of a battery. This will cause the motor shaft to turn to allow alignment as shown.

    Important: Inspect the encoder motor attachment face for the presence of the two (2) locating sleeves. If missing from the encoder motor, they need to be retrieved from the transfer case and reinstalled into the encoder motor before installation.

  14. Position the motor to the transfer case and install the retainers.

    Tighten
    Tighten the bolts to 16 N·m (12 lb ft).


    Object Number: 660281  Size: SH

  15. Apply pipe sealant, P/N 12346004 (Canadian P/N 10953480), or equivalent, to the drain plug threads. Install the transfer case drain plug.

    Tighten
    Tighten the plug to 27 N·m (20 lb ft).

  16. Refill the transfer case with 1.8 L (2 qts) of Auto Trac II Transfer case lubricant, P/N 12378508 (Canadian P/N 10953626).
  17. Apply pipe sealant, P/N 12346004 (Canadian P/N 10953480), or equivalent, to the fill plug threads. Install the fill plug.

    Tighten
    Tighten the plug to 27 N·m (20 lb ft).

  18. Lower the vehicle.
  19. Connect the Tech 2® and use SPS reprogramming to reprogram the transfer case control module (TCCM) with TIS software version 11, released October 2002 or newer.

Parts Information

Part Number

Description

88996635

Motor, Transfer Case Encoder, (Sensor)

88996636

Gasket, Encoder Module

12378508

(U.S.)

10953626

(Canada)

Auto Trac II Transfer Case Lubricant

Rexcars27, Service and Parts Director
Category: Car
Satisfied Customers: 147
Experience: 26 years in the automotive service and parts industry
Rexcars27 and 11 other Car Specialists are ready to help you

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