[modern] Re: Diff design , fluid refill problem

I fill the differential from the trunk, removing the bung that is
closest to the fill hole. Its the one over to the right I think.

I got one of my extra 1/2 inch extensions (I had 4 the same size) and
ground it down a bit on the part that fits on the socket, so it fits
in the hole at a slight angle, as the bung is a little off center.
Its a 1/2 inch, not 3/8.

When I do the fluid change, I jack the back of the car up quite a
bit…this tilts the differential away from the fill hole, and I get
a bit over two quarts into it.
The differential has a vent on the upper right side that will ooze
some gear lube over time, but thats ok with me…I think it oozes
anyway, even if the differential is low on lube.
Besides getting the plug out, there is the problem of getting the lube
in. I find it easy to warm up the lube, and using a fat hose, squeeze
it onto the differential.
pumping it up into a little hole where you cant see whats going on
seems like the hard way of doing it to me…you can see the level
through the bung hole with a flashlight.
Pull the rug out before the operation, and have a rag handy, as the
lube will want to push the hose off, and generally spill all over everything.
Put a pan under the differential during filling, and wipe off the
underside of the differential/sub frame/suspension when done so you
will spot any leaks in the future, and not leave nasty spots on the

I would strongly recommend filtering the lube thats in the differential
and re using it, toping up with some 85w140.
Use a coffee filter, or one of those fine screens meant to replace the
paper coffee filter.
Its one theory that the differentials start making noise AFTER the
lube is changed.
Its a good idea to filter out the metal and clean the magnet in the
drain plug, but reuse the lube.
If you do replace the lube, could you save it and send it to me?
I would pay for shipping…

1990 XJ6
…Date: Mon, 06 Mar 2000 10:34:59 +0000
From: John Archer jfarch@bigpond.com
Subject: Diff design , fluid refill problem
To: @Brett_Gazdzinski1


Thanks for your comments on the dif design . Hpowever I am still unclear
as to the actual designer and supplier of the diff to Jaguar. Maybe
someone else on the post might be able to add some comments here.

Yesterday I put the car up to drain and change the diff fluid. An hour
later I put it down again - no further ahead!

Problem 1. Couldn’t access the filler plug with a 3/8 extension enough
to properly seat it in the plug hole because the subfame ? is in the way.

problem 2. Whilst I noted the recent posts about accessing the filler
from the boot for the life of me i couldn’t see how my boot plugs could
give access to the filler. Is it the large one - about 3-4 inches
diameter roughly in the middle of the boot wall?

Also although Haynes says the diff takes 2.1 litres(approx) of fluid that
appears to be a lot of fluid for the volume of diff above the drain plug
to filler plufg. Is this amount of fluid correct or is a bit less?

I want to drain the diff and refill as this will complete my general service.

Might i add that replacing the upper wishbone bushes has been the best
improvemnt made so far. The car rides so smoothly and soaks up all those
road niggles that I was feeling previously.

All the best mate

88 Sovereign Silver Birch