LSD oil may harm your GKN diff?

[NZ fan]

Hi all, I have been trying to find the correct oil for my mk1 chim GKN Limited slip diff, the body plate says to use MobilubeHD90 which is a non LSD gear oil. I have emailed GKN and lo and behold they have replied as follows.

[fatboychim]

That's interesting, I've used this stuff for about 9 years now which is labelled as being suitable for LSD's

http://www.opieoils.co.uk/p-68901-fuchs-titan-race...

I try and change it every year or so. It gets plenty of track use and no problems just yet. What I do know is that when I very first got the car I changed the diff oil for a standard HD90 and I perceived a definite drag/vibration on the diff under load.
Not wishing to disagree with GKN about their own product but speaking from my own experience.

[NZ fan]

Thanks for that info. Maybe you have struck an oil that doesn't have the " harmful additives" that may degrade the seals. Tbh I have just changed from the standard HD90 to a Fuchs limslip oil but I couldn't stop thinking why does the body plate not specify a LSD oil hence my inquiries but I think you have proved that Fuchs Titan race is not going to hurt it.

[OleVix]

If the GKN in a clutch/plate type LSD you need the LSD diff oil, if its a helical gear type LSD use regular diff oil. GKN have many diff'rent diffs

[fatboychim]

Mine is also a 95 with a GKN diff and has the Mobilube HD90 plate.
GKN were fairly vague in their reply with words such as "likely" and "standard". Maybe they are contractually bound to plug the Mobil stuff as part of a supply agreement or suchlike.

ETA. There is no information on my car as to whether it is helical gear or clutch plate type diff, I assume it is the helical version as it carries the HD90 plate.

Edited by fatboychim on Tuesday 16th September 12:23

[NZ fan]

Sounds about right, I have looked up the drain hole on my diff and there are a number of holes drilled through the carrier that allow you to see the helical gears.. Very different to a clutch or cone type LSD. Mine is a 95 500 maybe (as Ole stated ) some are GKN clutch type they do indeed make many different diffs.

[spend]

The BTR folks dream of the (very expensive) Quaife upgrade to helical gear LSD...

You have them for free with the 'inferior' GKN diff

frequently msl:

[fatboychim]

spend said:

The BTR folks dream of the (very expensive) Quaife upgrade to helical gear LSD...

You have them for free with the 'inferior' GKN diff

frequently msl:

So just for clarity, do you know if all the GKN diffs fitted to early chimps are the helical gear type and also, if you wouldn't mind, what is your take on the use of oils labelled for LSD in them.