Is it okay for my to use Mobil Mobilube HD, Premium, High Performance, SAE 80W-90 for the diff in my Triumph Spitfire Mk3 1968?
Thanks
Normally it should be EP90 to GL4 spec (not GL5).
Landrovers also use this oil in their transmission, so if you have trouble to find it then I would go to one of the many 4x4 specialists in Iceland and either buy some from them, or ask where they obtain their own supplies.
The problem with using different oil in the axle or gearbox is that it may be harmful, but it takes a long time for the damage to show.
Ivor