Scraping/grinding front differential noise

[jmac219]

02 Envoy with 190K miles.
Within the past 2 days I started to notice a loud scraping and metal grinding noise coming from the front drivers side. I initially thought it was a bad wheel hub, but when I jacked up the front I noticed when I spun the drivers side wheel by hand it was making a clicking noise from the front differential. Similar to this video here.

Is my front diff screwed or could it simply be the CV axle?

Also 4wd Hi does not work. Only 4lo and AWD works. Not sure if those could be related.

 

[Mooseman]

I knew I recognized that video. It's from this thread:
https://gmtnation.com/forums/threads/front-differential-hum-not-wheel-bearing-video-included.13648/

 

[jmac219]

Thanks Mooseman!

I did some further testing today by checking the front diff fluid with a white plastic zip tie. Completely bone dry. I'm not even sure where the fluid went, because I've never noticed any leaks. I should have checked it sooner. Lesson learned. The bad news is there was a few small pieces of metal shavings on the fill plug. I didn't check the drain plug yet...

I'm sure the front diff is shot, but I'll try topping it off with the gear oil I have and see if the noise goes away temporarily. What is the worst that can happen? Will my wheels lock up while driving?

 

[Sparky]

Good thing is unless you were in 4x4 the diff isn't spinning under a load, just free-wheeling. I say fill 'er up with gear oil and see what happens. It may not be toast, as odd as it may seem. Might be worth putting some oil in it, running it a little bit to "rinse" it, drain the oil, and put more in to flush out any other shavings.

Unless it explodes it won't lock your wheels up.

Some fine metal shavings on the drain plug is normal. Chunks is what isn't normal.

 

[jmac219]

Update: I added a quart of some 75w-90 gear oil I had & took it for a spin. The grinding scraping noise went away, but when I turn the wheel by hand when it's on the jack it still makes the clicking noise like in the video. I haven't tested 4wd yet, but I'm sure damage has already been done. For now I will drive it and see if any of the new fluid leaks out. Otherwise I will find some time to repair it, or consider just removing the CV axles and front driveshaft to make it only 2wd like some others have mentioned on this forum. I don't really want to dump a ton of money into a 2002 with 190K on it. Thanks for the replies!

 

[Sparky]

How loud is the clicking? It could be unrelated to the differential. Mine always had a little bit of a small ticking when turning things, just from the needle bearings rolling.

 

[jmac219]

Well the grinding has came back. I inspected the front diff again and there was a some fairly large pieces of metal when I drained it. I'm pretty sure it is toast. I don't feel like putting any money into this truck anymore. I was doing some reading on the old trailvoy forums and read that it's alright to remove both front CV axles & the front driveshaft. What worries me is the hub. Will I have to keep the threaded stud end of the CV still attached?

 

[Mooseman]

Nope.

AWD/4x4 front diff permanent disable