Yes it is, Last year I pulled a locking rear diff (G80 RPO Code) to install in my 89 S15 Jimmy but what I did not know was there are different series cases depending on the gear ratio so I could not swap my ring gear to the new carrier. My original 3:08 was not compatible. However, Motive gears makes a 3:08 gear ratio thick gear set that would be compatible. I decided to tackle installing a Ring & Pinion gear myself and setting the pinion depth, backlash, checking gear tooth pattern, torqueing the pinion nut to the correct value and than breaking in the new gears properly. It all worked out. I did watch a lot of youtube videos.

 

You also need a few specialized tools. If you're not confident, and pretty mechanically inclined, it's probably better to leave it to a pro.

I've set up dozens of axles, and I still hate doing it. I'm just too cheap to pay someone else to do it.

 

Oh I'm mechanically inclined, and know more than your average Joe. But, I know enough, to know just how little I ACTUALLY know, if that makes sense.
Anyway I watched a bunch of rebuild videos, and that is definitely beyond me.
A full replacement of the rear end however, that, that I can do with a little help.
But back to a previous question, what should I do if when I pull the cover and find zero damage anywhere. What do I do at that point? Go ahead and do a replacement or just new gasket and rtv, and refill the fluid and just leave it at that?
I would prefer new, but financially that isn't feasible for me. So I'd really like to see if just refilling is even an option for me.

 

At that point, I would probably pull out the carrier with the ring gear, disconnect the driveshaft and turn the pinion by hand. If the bearings are bad, you'll feel it. Then you can decide where to go from there.

 

I'd still have to futz around inside? Lovely. Ok, thank you. I'll need to find someone to help with that.
If they're bad, will it feel like its hard to turn, or will I feel like a rumbling/ grinding type deal?

 

It's pretty easy to pull the carrier. And there's no "setup" involved, as long as you put everything back where it came from.

If the bearings are bad, they'll feel crunchy.

 

You could try to use a VIN decoder online or through a dealership to get a listing of all of the RPO codes instead of getting all greasy!

This is the one I used. Comprehensive Chevrolet, Saturn, GMC, Hummer, Cadillac, Buick, Oldsmobile, Pontiac, Geo, Dodge, Plymouth, Jeep, Chrysler, Ford, Lincoln, Mercury, Mazda Truck, Mercedes VIN Decoder. I think it costs a small fee though.

Edit: $5.00 for the decoding of 5 VINs. Not bad.

 

So if the bearings are still good, just replace gasket, refill and be done with it?

 

I would start by removing the drive shaft at the yoke. Then you can rotate the drive train from the yoke and at each wheel to listen and feel for binding or noise. I would make sure you can remove the fill plug before you take the cover off to make sure it is not stuck or stripped. You do have to remove the axles to remove the carrier. Just keep the bearing caps and shims for each side separate. Everything needs to go back where they came from. I am not a fan of using RTV on the gasket surfaces. I make sure that the housing and cover gasket areas are cleaned. I install the gasket dry and torque the bolts evenly. I have not had any leaks over multiple times, especially since I had to break in my Ring/Gears and change the diff fluid after so many miles. This is a personal choice and there are pros and cons with using or not using sealant on the gaskets.

 

I was finally able to pull the cover off. Immediately stopped and took a video and pic of what's going on. I'm gonna go out on a limb and say it shouldn't look like this.
Can't seem to upload the video. But the gouges you see there, are all around the outside of the centerpiece.
What now? Thank you again for your help, guys