ok i have a 92 Gmc k1500 4x4 regular cab pickup. My 4 wheel drive takes forever to kick in like 15 seconds. i have heard some people say that they have instant kick in actuators to replace the old ones for he front axle. I was wondering if they really do have those and where can you get them at. Id really like to be able to have almost instant kick in as soon as i pull the 4WD lever back. Thanks for all help.
On the full size, the front actuator is electric, not vacuum.
When in 4wd mode, a switch on top of the transfer case conducts 12 volts out to the actuator. Wire #50 (brown) is the 12v feed, and it conducts to the light blue wire (#900) to the actuator.
When shifted out of 4wd, the switch opens up and no voltage goes to the actuator.
I'll assume it is the actuator, if the plug to the actuator is getting 12 volts when in 4wd.
The way this actuator works, is it is a sealed chamber that gets heated by voltage. When it heats, the pin in the end swells and pushes a shift fork in the front differential. The shift fork engages a spline on the passenger side of the differential, and boom! you have 4WD.
GM offered an upgrade to this actuator that is a motor instead of a heated device. However, it requires a small harness addition, a spacer, and a new actuator. It is about a $150 to $200 option.
Good luck. The actuator is usually the problem 90% of time but recheck all of the wire harness just to maker sure there is no short before replacing any parts. The actuator may not be fully engaged or disengaged and the fork to the spline may be what is causing the whining or grinding noise you hear.
88-UP C/K ACTUATOR UPGRADE
VEHICLE SERVICED: 1994
CHEVROLET FULL SIZE
PURPOSE: IMPROVE AXLE CONNECT ENGAGEMENT TIME AND
COMPONENT RELIABILITY.
SYMPTOMS: NO FRONT DRIVE AXLE ENGAGEMENT WHEN SHIFTED INTO 4X4.
Obtain the following GM part numbers:
(1) 26060073 Actuator
(1) 88959465 Harness/Spacer Kit
