Removal Of Fwd Diff Actuator

[simon7mm]

Hello,

 

I am new to this forum and new to GMC products, any help is GREATLY appreciated.

 

I have a 2003 GMC Sierra, the Front Differential is not engaging. I am suspecting the actuator. To me it looks like it would unscrew, there is a section on the actuator that is HEX, looks like to get a wrench on.

 

I tried (with not much force) but was afraid to crack the plastic.

 

Has anyone removed one of these that could give me a bit of advice so I don't wreck it if it is not the problem.

 

Thanks in advance.

 

PS I have verified that it is not electrical problem, it is something physical in the diff.

 

JS

[Matt_]

It does just unscrew.

 

Im assuming that you verified that you have power at the plug with 4wd engaged and probably even tried supplying 12v to the actuator to verify that its not engaging?

 

Here's a thread on how the front diff works: http://www.gm-trucks.com/forums/index.php?...amp;hl=actuator

[Matt_]

And here's a replacement actuator:

http://www.monsterautoparts.com/CHEVROLET/...x4_actuator.htm

 

 

Oh... and welcome to the site!

[simon7mm]

And here's a replacement actuator:

http://www.monsterautoparts.com/CHEVROLET/...x4_actuator.htm

 

 

Oh... and welcome to the site!

 

 

Awesome! I am going to check it out today. I verified the power, and I can actually hear the actuator once power is applied, but the front diff is definetly not engaging. If it is not the actuator, I will have to take the diff out and have a look inside.

 

Thanks for the info...and the welcome!

Cheers

[Matt_]

How do you know the diff isn't engaging? It is an open differential.. so if you lose traction on one side that wheel will spin and the other won't.

[simon7mm]

How do you know the diff isn't engaging? It is an open differential.. so if you lose traction on one side that wheel will spin and the other won't.

 

 

There is nothing spinning in the front. This was my trouble shooting....

 

Under the truck,

- Shifter in 2WD - Front Drive shaft spins free.

- Shifter in 4Hi - Front drive shaft locked.

- Put from 2WD to 4Hi, I can hear the actuator. Unplug the actuator and shift back to 2wd - Shaft spins.

 

My brother's truck is identical...

- When 2WD to 4Hi I hear the actuator then a click, unplug actuator shift to 2WD - Shaft still locked.

 

This seemed to be intermittent at first, because the 4wd worked sometimes....Except when I needed it. now it doesn't work at all. Although I can hear the actuator when I am shifting from 2-4, I am hoping it is the problem. I spoke to people who have changed them before, but they didn't work at all.

 

I will remove it this evening and borrow my brothers to try.

 

Thanks