1991 GMC 4WD actuator how to replace and.

  • 1991 GMC C2500
  • 100,000 MILES

1991 gmc 4wd actuator how to replace and location

Thursday, December 13th, 2012 AT 1:28 AM

2 Replies

  • 68,496 POSTS

The actuator is mounted on the transfer case. It is just a matter of unbolting it from the transfer case and disconnecting the wiring.

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Thursday, December 13th, 2012 AT 1:53 AM
  • 25,476 POSTS

File In Section: 4 Drive Axle

Bulletin No: 76-43-01A

Date: September, 1998
Slow or no Engagement of Front Axle when 4WD is selected (Replace Front Axle Actuator)

1988-97 Chevrolet and GMC K Models
excluding 1988-93 Models over 8500 # GVW

This bulletin is being revised to add information to the Service Procedure, add a new part number, and include schematics. Please discard Corporate Bulletin Number 76-43-01 (Section 4 - Drive Axle).


Some owners may comment that the colder the outside temperature is, the longer it takes for the front axle to engage when 4 wheel drive is selected, or the front axle does not engage.


The front axle engagement actuator is a thermally activated component. Because of this characteristic, the time required for the actuator to complete 4 wheel drive engagement is extended as the temperature drops.


Replace the front axle actuator and include the applicable wiring harness kit. Refer to the Parts Information in order to determine which wiring harness kit is needed.

1996 model trucks with a build date on or after January 2, 1996 are considered as "961". If the build date of the truck is unknown, verify the 3 character "axle code" on the front axle label in order to determine which wire harness to order.

This new actuator uses a motor to engage the front axle and is not affected by temperature. On 1988-93 models with a GVW rating over 8500$, the new actuator cannot be installed and the thermal actuator will remain the service part.

Parts Information

P/N Description Qty

26060073 Actuator Asm, Frt Drive Axle 1
22510339 Fastener 1
15313272 Harness, Jumper (Z Splice) 1
(86-93 K1-3)

Parts are currently available from GMSPO.

Warranty Information

Some owners with actuators that are operating as designed (5-30 seconds engagement time) may choose to upgrade to the fast actuator at their own expense. The fast actuator is a new product enhancement and should not be used to replace actuators that are operating as designed.

For vehicles repaired under warranty, use:

it is on the right front axle area of the front differential


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Thursday, December 13th, 2012 AT 1:54 AM

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