Hey all, what's the best oil for rear diff of 2007 sti spec d setup? I've heard its a mechanical diff so needs different oil.
I wonder if Castrol driveline 75w90 will do the job as I've still got a decent amount of that...

 

Dunno what is best but I had Redline 75w90 put in the rear diff and 75w90 NS in the box at the 30k service

 

Butty what engine oil you running mate ? I have 10/40 Motul 300 but I might run 15/50 like my classic next time ?

 

Its Millers 10w60.

 

Cheers Butty

 

Thanks butty, I think that redline stuff is fully synth, castrol driveline synth fortified mix. How does the box feel with the ns? Any notchy bits when cold or hot or normal running?

 

Its a bit baulky when cold but very smooth when warmed up.

nick

 

A good choice is the Silkolene Syn 5

Silkolene SILKTRAN SYN 5 75W-90 Fully Synthetic Gear Oil

 

I have had this in my Spec D for two years and its been fantastic, never notchy when cold always smooth as silk

 

Is the Syn 5 ok for plated LSD's?

 

yes