Just wondering what I might be getting myself into financially if I have a shop do the repair. I’m waiting for a quote. What causes these to go bad other that it’s an old car?

 

Over time bearings can go bad if the preload wasn't set correctly. On limited slip differentials if they are abused the cross shafts can break, and that sends bits of metal through everything taking out the bearings. That was the case for mine, I needed to find the cross shafts, and as it had been abused rather a lot, I opted to replace the case. All I ended up using from my differential was the ring and pinion gears.This also assumes that it didn't simply run out of oil.

If you're not able or willing to do it yourself, I'd opt for a rebuilt differential from Coventry West. Simply removing and replacing the differential is a lot of work, the exhaust comes out, and the rear suspension comes out and is disassembled. There is a lot of "you might as well" things there, like replacing all the rubber mounts while they are out, and changing the U joints on the halfshafts, and the bearings and seals on the stub shafts should be replaced too. I don't know what the shop rate is, but I'd be surprised to get change from $5K.

 

Thank you for the reply. Very helpful info. I’m in way over me head if I’m looking at 5 grand to get that fixed. If the shop tells me It went bad because there wasn’t any fluid in the rear diff I’ll never forgive myself for my stupidity. But appreciate that tip about Coventry West.

 

Used rear assemblies are not all that hard to find and certainly a cheaper alternative than a remanufactured diff.

 

Yeah. I’m starting to get a better understanding of the rear differentials and the options out there. Similar to Jeep parts which is crazy! I had no idea the cross over on the jags with American suspension parts. Thank you!

 

Go to car-parts. com enter the year and you’ll be given a lot to choose from. I’m a racer, used has held up in decades of racing. Buy used, check the oil for metal partials. If you find any, send it back for another one.
Now there are enough Jaguars near me in junkyards so I just take my pick. I go there, Pop the rear cover off, stick my finger down in the oil, rub it together. Metal? Cover goes back on and I check the next one. It’s pretty rare that they are bad though.