Diff Investigation and queries - help please

Today I finally pulled apart the XP Ute diff. Here are some pics of the damage and some questions.

I found the cover had been sealed on with silastic rather than a gasket. Until this there had been no need to take the cover off the diff so the repair has been in place for at least 9 years

With the cover off it initially didn't look too bad
http://farm4.static.flickr.com/3116/2600169744_a5f28acee1.jpg?v=0

so I inspected a bit closer and something didn't look right
http://farm4.static.flickr.com/3028/2599345565_ff45072b30.jpg?v=0

the teeth on the pinion indicate its most valuable as scrap!
http://farm4.static.flickr.com/3200/2600206378_fb38d7c984.jpg?v=0

where the pinion shaft comes into the housing there

Even my very limited knowledge is enough to know this shouldn't be there


cleaned out the crud and here it is
http://farm4.static.flickr.com/3170/2599373053_083b7115b9.jpg?v=0

the two rings are bearing covers of the ends of the axle and appear to be ok. The mangled mess between them appears to be a cover which holds the rollers in place. At the top is the rollers and bits of teeth.
http://farm4.static.flickr.com/3072/2599354719_4b3fc33dae.jpg?v=0

The crown wheel had damaged teeth and it looks like the pinion had been chewing the casting. Is the casting still usable or has it been weakened and now only scrap?
http://farm4.static.flickr.com/3206/2599359369_1ece6919b3.jpg?v=0

To me the spider gears look to be ok as I can't find any chips on them. Are they reuseable? The reason I ask is the ute/van diff has a different axle diameter to the car/wagon/coupe. If I can replace the pinion and crown wheel (which is bolted on) I can recondition this diff.
http://farm4.static.flickr.com/3061/2599363507_c9fa0868c3.jpg?v=0

There is a mark at about the 10 o'clock position where the housing has been chewed by something. Is this an issue or can I just remove the bur and everything will be fine?
http://farm4.static.flickr.com/3037/2600211138_0240cf5935.jpg?v=0

The seal where the pinion shaft enters the diff is now also out of round but I think I can get a new seal.
http://farm4.static.flickr.com/3061/2600216274_64e2c9ba53.jpg?v=0

So is it worth keeping the bits to rebuild the rear end to a 5 stud diff or should I make the front end 4 stud as well and fit disk brakes (which are not available in 5 stud for these only later models)?

Seeing as you already have a higher speed diff fitted, it makes sense to keep it and reap the benefit of better fuel consumption or cruising speed whichever you prefer. That being the case and keeping in mind todays traffic I would go for the disc brakes and leave the diff alone.

Agree with Ray. Why go slower. Why not go fast and improve the brakes etc.

Certainly could keep some of the parts just in case. But if you wanted to use any of the parts for long periods I would suggest you would want to get them crack tested or x-rayed to find out the condition. Especially since the amount of damage that has occured.

Personally I wouldn't think it would really be worth it. Especially since it is so different to what you are now using which is also easier to repair or replace in the future. Would you ever want to go back to the old diff?

bparo, I will say one thing, OUCH, you did a great job

I think that one is for the books.

Maybe I should explain a bit.

The 5 stud axles run bigger drums in both diameter and width and bigger shoes to match (1 inch longer and 3/4 inch wider). They also run heavier duty bearings. I am not sure if I haev mentioned it in this thread but the axles are also heavier duty

The crown wheel and pinion are interchangeable but the spider gears are not.

I was not actually planning to pull out the new diff but maybe find the bits cheaply over the next couple of years and rebuild the 5 stud as a spare as I have no intention of selling the XP while I can run it and bits are only likely to get harder to find.
Its a good, reliable vehicle and it would be hard to find another one in original condition. This was the 1st time in 8 years it hadn't got me where I was heading.

I was going to try and find another 3.2:1 centre (as the new one is) and put the crown wheel and pinion into this housing and carrier (which is why I asked about the damage to it.) This would give me the cruising speed with a heavy duty rear. It is not worth the hassle of pulling the current diff back out again but it may be worth building up a spare over time

As truckies know braking is about surface area and the 11 inch ute drums have more braking surface than the disks and will actually stop in a shorter distance but they fade faster so are less consistent but have yet to be a problem even when I drove it to work as a daily driver.

Does that help explain my reasons or just confuse the situation further