My first differential failed at 90,000 miles. 40,000 miles later I'm being told it may be going out again. Two questions here:
First, what can I do to find out if in fact my differential is going out again? Is there something I can check; what do I look for/watch for?
Second, is anyone aware of a retrofit to a more solid differential? I know Jag rear ends were sought after for hot rods; what happened? Somebody screwed up a good thing apparently!
Help! I can't afford to drop another $2500 to keep it running.

Dave

 

What symptoms are you hearing or feeling that make you suspect the diff?

Excessive metal content in the oil would suggest a problem, as would grinding, growling, clunking, chattering. A whine sound that goes way on closed throttle is another clue.

Sometimes a failing rear wheel bearing can be confused for a differential problem









I've not heard of any, personally. Others will chime in.






Someone at Jaguar decided that the older, over-built differentials were a waste of money.

:-)

I think the hot rodders loved the old Jag rear ends because they were in a completely self-contained subframe assembly and easily adapted to other cars. The fact the the differential itself was very robust was just a bonus :-)




Any hope of DIY differential swap to save a ton of money?

Cheers
DD

 

Any 3.58 : 1 final drive from 1989 XJ40 to 1997 X300 will fit your car (as long as it has the JURID coupler and not the flange from the early 1988 XJ40 models).

The pinion bearings are the ones that make the higher pitched whine when they start to fail. The output axle bearings are easy to replace and make a lower pitch when failing/worn. The also have alot of axial play when the ball bearings fail (negative camber in the rear wheels).

I have rarely seen the 2 carrier bearings fail in the diff unless there is alot of metal in the oil from other failing parts.

I used to charge around $1100-$1200 parts and labor to remove, replace all the bearings/seals and reinstall a final drive in the XJ40/X300 cars but I have not done one in 5 or 6 years.

You might get a good used but make sure it's good before you spend the 9 hours to R&R.

The carrier bearings are the hardest to replace and make sure you put all the shims back in the same place.

(I have never needed a case stretcher but it does take a little finesse to get the unit fitted to the case with a hammer and a block of wood (just hold you mouth right)).

bob gauff

 

Thank you for your response. The fact is, I didn't suspect a problem until my indi shop told me it was starting to go out. (Not the same indi that replaced it the first time- I wonder if they just said it because 130,000 is 'overdue' for this in their books!) Then just last month I noticed the car blowing smoke for the 3rd time in its life.

From an earlier post: "The first inkling of a problem was in 2006 on the way to Vegas when it started blowing smoke. I pulled over to check for an oil leak somewhere or an overfilled crankcase or anything- couldn't find a thing. Ran fine the rest of the trip. It wasn't until a couple months later that it started blowing smoke again and suddenly ground to a halt, barely making it to the shoulder of the freeway."

I am always aware of little noises or rattles; things that just don't seem right, so when the diff went out on me it was a complete surprise. Now I'm relating that smoke with the diff again. As before, I checked for any kind of oil leak and the only thing I noticed was an oily film on the rear bumper and trunk- in the first instance, not yet now.

So actually, no unusual noises that I would associate with a rear end problem.



Well my buddy Cybersib said he would be happy to help- I haven't been my own mechanic since my hotrod days in the '70's, but I could give it a go again... for this kind of dough!!

Thanks again for your responses guys!

Dave

 

Bingo!

The differential breather likes to clog on these. Then the lube gets pushed out past the seals from pressurisation when the diff heats up. Oil film on the bumper is a classic sign of a leaking diff.

So, you would replace the breather, refill the diff and cross your fingers.

Credit goes to Motorcarman has posted about this multiple times in the past.

 

Thank you my friends! Perhaps we can now avoid the nightmare... (crossing fingers and toes- hard to walk now...)

Dave

 

One other thing.

Wash off the affected areas, although it does make a great rustproofing, and monitor the film on the bumper. It can warn you when you need to top or replace the seals.

Some cars can go for years with a minor leak as long as the lube is kept topped up. A little whiny, annoying to fill up, but nothing close to death.

On a brighter note, it may be that once the vent is working properly, all goes back to normal because it was caught in time.

 

Ahh, yes. I will clear the 'tell' from the bumper so I can monitor the vent's and seals' condition. I don't need the rustproofing here in So Cal, and the boats I sail and work on are from 32' Cutter to 135' Brigantines! I don't use the car to launch anything, so that won't be a problem for me.

Thank you again, I feel like I have renewed joy with my cat again!

Dave