Changing Differential Fluid

[Blanford]

1985 CSi
Manual calls for 90w.
What is the consensous? 80-90?
I don't want to use Synthetic as its always had conventional oil.
Lucas has an 80w90 that says its excellent for LSD's however their chat support says add LSD additive. Bit confused and I think he was to.
Any feed back appreciated.

Iain

[EuroGeorge]

Straight 90W gear oil that is not synthetic is getting harder to find. Most are multi-grade, 75W-90, 80W-90. I have used 80W-90 hypoid GL5 from Castrol. Seems like I can't find that anymore. I used a bottle of BG LSII limited slip additive with a change. PJ1 makes a straight 90W hypoid GL5 oil for shaft drive motorcycles. I used it on my FJR1300 and it liked it.
As long as you use a hypoid GL5, you should be good. See what others have to say.

[Blanford]

Found some Castrol 80-90 for LSD. Gona give it a go.
Anyone replace the main seal in the diff?
Thanks EuroGeorge for the reply.

Iain