Thread: Gearbox Oil Disco

I've been using the Penrite Light Gear Oil 75 (75W/80) in R380 gearboxes for quite a few years now and have had no problems.

Don't under any circumstances use a heavy grade oil in the R380 gearbox as I believe there is an oil pump within the R380 gearbox that requires the lighter grade oil - similar to the originally specified auto-trans oil.

I have also found that the regular addition of a 'dose' of Nulon R70 to all transmission oils helps, especially in the case of 'notchy' selectors.

Roger

My disco manual is now changing smooth as silk. Had all my oils changed last week using 75/80 penrite in the box. It has never felt so good and warms up a lot quicker as well. My gearbox oil gets changed every 20,000 and it is always dirty black colour the diffs and transfer are always clean. what makes the gearbox dirty? There was no metal on the magnet.

Mike