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Which dif Oil for LSD from a Sierra Cossie?
tbox - 4/3/12 at 03:30 PM

Hi all,

As per above, i'm fitting the LSD originally from a Sierra Cosworth and I'm hoping someone will be able to advise on the best oil(s)to use with it?

All the best

T-Box.

snapper - 4/3/12 at 03:32 PM

Standard stuff as the LSD bit is sealed

tbox - 4/3/12 at 03:50 PM

quote:
Originally posted by snapper
Standard stuff as the LSD bit is sealed


Many thanks Snapper. does that mean that it doesn't require any special additives for LSD's?

sorry for the naive questions... bit new to all this!

britishtrident - 4/3/12 at 04:44 PM

It is just an ordinary final drive with a viscous coupling, the viscous coupling bit is completely sealed from the final drive oil. so you can just use any ordinary EP 75/90 Hypoid gear oil to GL5 spec.

tbox - 4/3/12 at 09:23 PM

Thanks for the clarification. Very useful!

Rob Allison - 5/3/12 at 04:45 AM

EP 80/90 is the book spec for the sierra

tbox - 5/3/12 at 08:24 AM

Thanks Rob... If that's what the book says, then that's what I'll do!

britishtrident - 5/3/12 at 09:02 AM

Things move on the original oil fill back in the 1980s was actually straight EP90 GL5

EP75w/90 is a multi-grade and supersedes EP80, EP90 and EP80/90

It is the GL5 bit of the spec that is important

GL spec number is important because the gearbox lubricant is specified as EP80 GL4.
GL4 and GL5 oils should not be confused.
GL4 oils don't give enough protection for the final drive hypoid gears.
GL5 oils aren't good for the gearbox synchromesh mechanisms.

[Edited on 5/3/12 by britishtrident]