Front Differential Engagement Problem

**destroyer1362** · 05-09-2009, 05:03 AM

I have a 2000 Denali 5.7. The front differential does not seem to engage. I have ruled out everything else. (1) What I want to know is has any else heard of a washer becoming malformed which could prevent the front differential from fully engaging? I am thinking about doing the repair myself because it's a $3 dollar part and I don't want to pay the labor on something like that. Once I pull the diff I am only planning on opening the part of the case that the actuator goes into, not where the actual ring and pinion are. (2) Is there anything that I could mess up in this part of the differential by opening it? On a side note; I have fixed things similar to this in the past, so I think I should be up to it. (3) And does any one know what that silicone sealant is called? so I will know what to look for when I close this thing back up?
Thanks

**Jimmiee** · 05-09-2009, 08:42 AM

Originally Posted by destroyer1362

I have a 2000 Denali 5.7. The front differential does not seem to engage. I have ruled out everything else. (1) What I want to know is has any else heard of a washer becoming malformed which could prevent the front differential from fully engaging? I am thinking about doing the repair myself because it's a $3 dollar part and I don't want to pay the labor on something like that. Once I pull the diff I am only planning on opening the part of the case that the actuator goes into, not where the actual ring and pinion are. (2) Is there anything that I could mess up in this part of the differential by opening it? On a side note; I have fixed things similar to this in the past, so I think I should be up to it. (3) And does any one know what that silicone sealant is called? so I will know what to look for when I close this thing back up?
Thanks

It's a straightforward replacement. There are many posts here on how to replace the actuator if you care to do a search. The one trap is the wiring. There's an extra wire on the later trucks and the GM actuator fits all models so if you have an early truck you will have an extra wire. The instructions show how to wire it up.Have fun!

**destroyer1362** · 05-09-2009, 02:19 PM

Thanks for the reply, but its not the actuator thats giving me problems its something internal unfortunately.

**GaryL** · 05-11-2009, 09:38 AM

Check out this thread and see if it might help you out. I emailed you the differential pdf's a little bit ago.

http://www.gmtruckclub.com/forum/showthread.php?t=2509

**destroyer1362** · 05-13-2009, 02:15 AM

Thanks for the pdf's and the link. I was about ready to pull the front diff for a rebuild, now I may not have to. I'll keep yall posted on what I find.

**destroyer1362** · 05-25-2009, 02:58 PM

So I finally got around to pulling the diff and found the problem...

The only way I see this happening is if it was done during assembly.. according to the carfax it never had any diff work done before. And does any one know if I can use Permatex Black Hi-Temp RTV sealant to seal the right axel tube back up?

**bl97tahoe** · 01-07-2010, 11:35 AM

i am having the same problem. How hard was it to pull everything off?

**Viper** · 01-08-2010, 09:56 AM

black or red hi-temp however make sure nothing gets inside the case or you'll be pulling it apart again, make sure you clean the matting surfaces real good and if you want get some 1000 grit to make sure its really clean and only use enough to seal the case it should be a machined fit anyway