Can 85w 140 work in the 1996 4.0 non-LSD Jaguar X300 differential?

 

Many members are using 85/140 synthetic. Do a search for differential fluid.

 

Service manual says EP90, 140 is too thick. I always use 80W90 and I have a LSD differential.

 

Have not found anyone yet on the forums using 85w140...

 

Multi-grade oils like 85W140 can be thought of as having the high temperature protection of a 140 weight oil but the cold temperature flow of an 85 weight oil, so 85W140 is a great choice for your Jaguar diff. In our '93 XJ40, which has the same GKN Salisbury 15HU diff as most non-LSD X300s, I used Lucas conventional 85W140 gear oil for many years. I rebuilt the diff several years ago and while the bearings were worn out, the gears were in superb condition. After the rebuild I filled the diff with Lucas synthetic 75W90, and a few hundred miles later I drained it and filled it with Lucas synthetic 75W140. The diff has now done 197,000 miles.

BTW, for those who have a Powr-Lok or other Limited Slip differential, then in addition to the right gear oil you may also need an LSD oil additive to prevent chatter or bumping while cornering.

Cheers,

Don

 

Thanks for the insightful response Don!

 

Redline and Amsoil both have an interesting mid-point gear oil that is synthetic 75w110

https://www.redlineoil.com/75w110-gl-5-gear-oil

https://www.amsoil.com/shop/by-produ...-gear-75w-110/
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How much single rear wheel spin will the power look allow before locking up?
I have always assumed my XJR has the LSD. Certainly the rpm in 5th gear match the ratios for the 3.27 LSD and 290 Getrag gearbox

The other day I got a wheel on the grass verge and spun it up - the speedo climbed about 30 km/ h too high, so a fair bit of single wheel spin.

 

An XJR ought to have the LSD, but you can check by looking at the differential. The case will have a tag with a big "X" on the side of the differential. I think the "X" is orange, or maybe the tag is orange with a black "X", I forget.

But I have no idea at what wheel RPM the LSD clutch pack should start to lock. Interesting question. Also I'd assume that the LSD comes on gradually, not binary on/off.

.

 

The spec to break away is between 50-80 ft-lbs. It's not a huge amount, otherwise you'd never be able to turn a corner.


The locking part is actually always locked, it unlocks when needed, such as when turning.


The way to tell if you have LSD is to jack up the rear of the car and leave the shifter in neutral. Spin a wheel by hand. If the other wheel moves in the same direction, then you have LSD, if it moves in the opposite direction, you have an open diff. Another test is block one wheel to prevent rotation - wedge a piece of wood under it for example. Then turn the other wheel. If it turns easily, you have an open diff.