NEED HELP Gorgeous Final 500 Olds Bravada w/97K and 'front differential' issues -- will I have to scrap it?

[RiverGuy]

This '04 Final 500 Oldsmobile is my THIRD Bravada, and has been near-perfect since I paid way too much for it in 2014 with only 57K miles.

Bottom line -- it appears the cost of repairing the passenger-side axle seal in the 'front differential' will be more than the vehicle is worth -- looking for lowest cost repair options/ideas.
(Disabling the AWD option and reverting to RWD has been considered, not viable for us.)
Recent events:

1. In July of last year the NP4 (full-time AWD) transfer case started making that grinding sound...
2. Paid a reputable local mechanic to swap the transfer case out for a used one I had shipped to them.
3. Local mechanic noticed that the shipping crate was badly damaged, but apparently did >>not<< notice that the replacement xfer case was cracked.
4. Everything seemed fine, but then the driver's side front Differential/Axle seal started leaking (unrelated issue), had that replaced and then...
5. First snowfall came and realized that there was no torque getting to the front wheels (confirmed with my Tech2). Strangely, there was never a code thrown until I tried getting up a hill and let the rear wheels spin for about 30 seconds...
6. Last week, GMC dealer mechanic found the cracked transfer case. Paid $$$ to have another used transfer case installed.
7. Picked up the vehicle and AWD is now fixed.
8. Drove the vehicle about 15 miles back home, parked it in the garage, came back out 2 hrs later and smelled gear oil. Found a BIG puddle of beautiful, clear gear oil on my nice clean garage floor, under the right side of the engine...

Probable diagnosis is that the shaft seal between the 'front differential' and the oil pan is completely blown out.
This seems like too big a coincidence to swallow it whole, as that seal did not leak a drop in the four months between having the driver-side (outer) seal replaced and yesterday. Before I spent the money to have the outer seal replaced, I had the mechanic confirm that the other side was completely dry.
One thought came to mind -- is it possible that the differential vent-tube became blocked/kinked somehow, causing pressure in the differential to build up as the gearcase heated up and blowing out through the seal? I just can't imagine how both of those seals would be blown out in rapid succession with only 97K miles...
Any thoughts or creative solutions welcome -- but again, we need the AWD to be working in the end...
Thanks in advance!

 

[Mooseman]

Man you've had bad luck with it. That seal can be replaced but the front diff has to come out. A fairly long process but one of our members has developed a method of getting it out a little easier than what the manual says. You mechanic was probably going by the book, which says you have to remove the oil pan, for the number of hours so this may be its saving grace.

How to remove front differential from the bottom (easier)

Then there is the other way from the top.

How to remove front differential from the top

 

[RiverGuy]

Wow...thanks! I have a mechanic I have worked with for 20 years, I'm going to have him take a look at this procedure and see if they will do it.

SO HELPFUL!!!

 

[Mooseman]

Hope it saves your Bravada. I don't think there are too many left out there.