Hey everyone who's drained the diff & replaced gear oil... do you recommend only using the $50+ per quart from dealership mineral oil or do you guys use some other synthetic? Much safer to use the OEM?
Thanks

 

I use ordinary [Valvoline] [Shell] [Quaker State] [whatever is on sale that day] 80/90 gear lube. If you have limited slip use LSD additive or buy the gear oil that's labeled "for limited slip".

Cheers
DD

 

Thanks Doug!
Are any x300s not limited slip diffs? The xjr is open diff? Id hate to get the wrong oil, im pretty sure my 97 Xj6 base model is LSD and not open diff
Anyone beg to differ?

 

USA market cars were not normally fitted with LSD. It was optional on other X300s for other markets.

Limited slip was standard issue on the XJR/6, regardless of market.

Cheers

DD

 

Not sure about your bit of the world, but down here, most diff oils are LSD compatible, coz a non-LSD diff does NOT get hurt with LSD oil, but a LSD diff with non-LSD oil is not a good idea.

Some of the cheaper brands are still LSD specific, and the synthetics are a maze and I dont use them.

If in doubt use a good quality LSD oil, and drive on, as Doug said, different markets got different specs, such as ALL V12 are LSD.

My 3.2 is non-LSD, and it just got changed with Penrite 80W/90 LSD oil coz that was on special on that day.

 

Thanks for your input Grant. I figured that LSD compatible oil is the way to go just incase the previous owner opted to get LSD diff. Its good to know that gear oil w/ additives compatible for LSD will not harm an open diff
thanks again everyone for the help

 

If you have an LSD or not is an easy check though. Rasie the rear of your car so both of the wheels are of the gronud then turn one wheel.

If the other wheel goes the same direction the you have an LSD and if not you don´t.

And any diff oil should work these cars hava Dana 44 axles same as in alot of American cars

 

according to that test, I have an LSD Diff on my 97 X300
who knew? haha perhaps the previous owner that bought it from Jaguar Honolulu opted for the LSD. Good to know
Thanks again

 

I have a rebuilt Power-Lok diff/final drive in my 96 XJR6 - the previous owner had it the pinion shaft seal replaced and the shop did not stake the pinion nut in place - it got loose while driving -> not good, at all...
I have been using Motorcraft 75W-140 with the Motorcraft XL-3 limited slip additive in it. Works great. I read that some of the older Salisbury differentials used in XJ Series I/II/III, XJS, and E-Types used leather seals that are supposedly not compatible with synthetic gear oils. The later X300 diffs (same construction) but updated seals will be fine with synthetic gear oil.