15HU differential input shaft play
 

Dear gents,

A few months ago I substituted my old diff due to play in the input shaft (MY 2000 XJR, approx 140k mls on car & old diff).
Having the old differential now sitting on the shelf, I'm wondering what kind of work is involved to get rid of this issue, so that it'll serve as a intact spare one day.

The diff is clean and tight. The oil had been replaced last year - oil level still good. No oil leaks - neither before nor after the oil change. Vent mechanism is clean and free. No squeal, no noise, no other play than in the input shaft.
When turning the input flange back and forth the play can be felt. It's no axial involved but approx 1-2 degrees of rotational play .

Any ideas, approaches or experiences on how to find out what's wrong and how to cure the issue?

I'm quite familiar with turning the wrenches at our Jags, but I never had anything to do with differentials. I do know that there's sometimes fitting components under preload conditions involved, but that's a closed book yet. Nothing that I'm not willing to learn but there's only little prior knowledge to differentials.


Thanks in advance and best regards, Alexander

there should a a small amount of backlash you can feel by hand when the diff is setup correctly, 4 thou 0.004". Not enough backlash, they're noisy and don't last very long. Setting them up is involved, alignment with clock gauges, tooth angle etc. Adjustment with shims.

Thanks Sean for your reply!

Let me guess, there's no manual or any other documentation available to dig in and get further info?

Any Jaguar service manual going back to the 1960's covers drivetrain and final drive servicing, including the diff. From the HU4 onwards they're pretty much similar, of course the limited slip are not applicable to our cars unless there's a need ;)

I attach a few documents that I gathered before doing work on my BMW E30 M3 differential and also documents on Dana diffs (I had a Daimler Double Six in the past).

The attached pages are related to the BMW E36 M3 differential.

Found one more document for Salisbury diffs (Jaguars of the 80's had Dana or Salisbury).

Wohooooo...thanks a lot! I'll have a lot to read this weekend! I'll report back as soon as I sifted through your uploads :-)