Replacing or rebuilding front differential

[holytornado84]

I am about to start tearing down both sides of the suspension on my 2004 LS Trailblazer 4x4. I know that the front differential is petty much gone. Constant grind while driving.

I was wondering if anyone on here has replaced or had one rebuilt and what possibly would be the best way to go about this project. Thanks for any info

 

[HARDTRAILZ]

Its a bitch to get out or put back in. Rebuild is basically like any other gear setup.

Look at offroadtb.com for the notes on getting it in and out through the top. Many find it easier that way. I did mine through the bottom with a lift and the steering rack removed and it sucked still.

 

[Nexus1155]

Hard is right. It isn't fun at all. I recommend replacing since it is so cheap nowadays for a unit or even upgrading internals like said on offroad if you are so incline. I mean. Why is it grinding to begin with? Once it starts its almost game over

 

[Mooseman]

You sure it's the diff and not the disconnect or half-shaft? They have been known more often than not to fail.

 

[holytornado84]

I replaced the front axle disconnect on this same truck in another thread on here a few years back. I have only drove the truck 30k since then. The front diff has had a leak since I have owned the car. I can't keep it filled. Overall, I have driven the car 112K since I bought it.

When I started this project, I put the car up on jackstands so that all four tires are off of the ground. I switched over to 4-hi and only the back wheels and the front driver side is turning. Got under the car with a stethoscope and the grinding noise while the tires are spinning is coming the loudest from the differential.

Since then, I have tore down both sides and removed both axles. It looks like the outer seal where the front passenger axle sticks into the disconnect has failed. There are also lots of bearings everywhere when I removed the axle out of the differential. I haven't pulled the differential yet but plan to in the next few days. I will attach a photo that I took of the differential with the axle removed. I'm guessing I'm going to have to somewhat rebuild the front axle disconnect along with either rebuilding or replacing the front differential as well.

 

[Tiggerr]

I replaced the front axle disconnect on this same truck in another thread on here a few years back. I have only drove the truck 30k since then. The front diff has had a leak since I have owned the car. I can't keep it filled. Overall, I have driven the car 112K since I bought it.

When I started this project, I put the car up on jackstands so that all four tires are off of the ground. I switched over to 4-hi and only the back wheels and the front driver side is turning. Got under the car with a stethoscope and the grinding noise while the tires are spinning is coming the loudest from the differential.

Since then, I have tore down both sides and removed both axles. It looks like the outer seal where the front passenger axle sticks into the disconnect has failed. There are also lots of bearings everywhere when I removed the axle out of the differential. I haven't pulled the differential yet but plan to in the next few days. I will attach a photo that I took of the differential with the axle removed. I'm guessing I'm going to have to somewhat rebuild the front axle disconnect along with either rebuilding or replacing the front differential as well.View attachment 80463View attachment 80464

Looks like the bearing itself could be the cause of your noise. Think I'd replace that bearing before I pulled the diff. (Provided you can do it without pulling the diff anyway) I'm 2wd so I can't say for sure but from what others have said that diff is a bastard to get out.

 

[Sparky]

Dang that thing is really rusty inside. Totally shot, ouch.

 

[Mooseman]

Was maybe low on lube, hence the rust and destruction? I'd just find a good used unit, put on new seals, throw it in and call it a day.

 

[holytornado84]

Does anybody have any experience in finding these units anywhere? I have found a few on eBay for around 600 bucks but didn't know whether that was a good price or not.

Also, does anyone know where I can find the seals and possibly the kit to rebuild the front axle disconnect?

 

[mrrsm]

These guys have a variety of GM Front End Differential Components... with cross related GM part Numbers shown for comparison and no expectation of "Core Returns". This link relates to their intro page...but the data there relates specifically to your 2007 Four By ...

http://atpautomotive.com/4wd-front-axle-disconnect-111159

 

[Mooseman]

Check car-part.com for your area. Avoids shipping and prices should be better than fleabay. Or just start calling around at yards.

 

[holytornado84]

Well, I have been a little busy up until the last week or so with active weather throughout the alley. I did however pull and replace the front differential a couple months ago and in the process, I was able to get some descent footage of the pull. Figured I would go ahead and finish up this thread and post the video here explaining most of the bigger steps in the removal.

Sorry, I didn't realize I almost hijacked my thread with my last post. @Sparky or @Mooseman if one of you guys wouldn't mind deleting the last two messages before this one (the two about the ball joint) so that this thread stays on topic please. Also if ya'll wouldn't mind changing the title of the thread to something more fitting. Whatever ya'll think would fit it properly. Thanks again to everyone for the advice on this repair.