I use 75/90 hypoid gear oil on my Gen2. I'm not sure what the older models use but the manual for the gen2 clearly states that you should only use gear oil intended for Hypoid gears. Last year I used regular 80/90 gear oil on everything and the gearbox burned the oil in no time, so did the rear diff. I'm not sure if I did any real damage but I'm sure time will tell.

If someone has a owners manual from a '87 please check it out and post here because I heard that this is the most common cause for the gen2 gearbox to die over here.

1987 SWB Pajero 2.5 TDI on 31" rubber waiting for a hip replacement and bigger shoes