Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing What oil for +8 LSD back axle?

Castrol have stopped making Hypoy LS apparently and there's now a product called Castrol SAF-XJ SAE 75w-140 Fully Synthetic Hypoid Gear Oil
First of all, is this a suitable oil for a 1988 +8 differential?
Secondly, noting it's synthetic, will it still need the magic little bottle of Jaguar additive?
What other manufacturers' products are preferred today for this final annual crawl-under Spring rite?
Thanks for all ideas/comments

Just make sure that the Castrol oil contains the LSD additive (friction modifier), although you can get that from Demon Tweeks.
Morgan use Morris Lubricants............

http://www.morrislubricantsonline.co.uk/scripts/prodView.asp?idproduct=68&product=Lodexol+XFS+80W%2F140+Fully+Synthetic+Limited+Slip+Gear+Oil

80W/140 is recommended and is fully synthetic rear axle oil for high performance vehicles. Morris Lubricants have already added the friction modifier to their oil so there is no need to buy the modifier separately.

Other rear axle oil that is approved to be fitted to BTR units are:
Castrol SAF-X
Castrol SAF-XA
Mobil SHC 80W-140
Mobil SHC 80W-140ID
BUT - if any of the above are used then they will require the friction modifier to be used along with the oil.

BMW dealers also sell an LSD oil, but I've misplaced the part number.

I'm with Morris - originally used semi-synth plus friction modifier, but now have fully synth as per the link.

I might also add that the light chatter I got when reversing has now disappeared.

Brilliant response as usual Dave, many thanks
I have ordered 2 litres from Morris and to re-affirm what you have said above, their fully synthetic oil does NOT require the additional friction modifier ...? I ask this because I thought my 1988 car was still on a Salisbury diff, not BTR, but how could I tell the difference, and does it matter anyway to the oil spec?

It could be Salisbury with a Quaife LSD, but the Morris oil does have friction modifier so it should be fine. It takes a long time to drain by the way - and remember the golden rule...... take the filler plug out first, before you drain it. the Salisbury has a drain plug in the bottom of the casing. The BTR drains through one of the rear cover bolts.

A bit more detail here.....
http://www.talkmorgan.com/ubbthreads.php/topics/30883/1

So Dave, with a fully synthetic oil, do you still get the viscosity degradation within 12 months that necessitates an annual oil change in the diff?

Not according to Morris's
G

John
Your 1998 +8 will have a GKN-Salisbury axle with the Salisbury (not Quaiffe) limited slip diff (unless it has been replaced with a BTR one). I think you should take a look at http://www.gomog.com/allmorgan/axlefilling.html which gives some details of oils - in particular it suggests you do not use the same oil as the BTR. The recommended oil grade is EP90 or 85W-90 which are lighter grades than the 75W- or 80W-140 that you are planning to use. I notice that Millers do a lim-slip EP90 (XEP90) oil which appears to be a direct equivalent of Castrol Hypoy LS. It is a mineral-based oil so you would have to change it more frequently than you would a synthetic. The handbook for my '93 +8 (same axle as yours, I think) recommends every 5,000 miles.

Maybe others have tried the new oil in the older axles - I don't know - if so it would be interesting to hear from them.

The Gomog link has the BMW part number which I had misplaced!

I came across that post before I did my first service, and then "asked around". You really need to draw your own conclusions as to which oil to use on a DIY refill. The recommendations in my post above are from a source which I have confidence in re the BTR axle.

I used semi synth 80/140 in a Salisbury diff (without LSD) for many years with no problem.

I'm definitely on a Salisbury diff but on the assumption that by definition, newer synthetic oils weren't around in 1988 and are complete with all friction additives - and I've ordered two litres from Morris which should arrive tomorrow, I'm going to volunteer to test this on behalf of the group ...
Meanwhile, I'm off to watch the final stage Flying Scotsman Classic Trial almost going past my door this afternoon - here's the entry list! http://www.endurorally.com/fscot2011/entry.html so should be a good run out