Right Oil for BN1 axle and gear box

[LuckyLuke]

What oil is best for the axle and gear box? My owners manual says W140 for axle, some say W90

 

[Dave Richards]

Keoke, or Dave Russell, I got some LucasOil for the steering box, can that be used in the rear end of a BJ8?

 

[Keoke]

Keoke, or Dave Russell, I got some LucasOil for the steering box, can that be used in the rear end of a BJ8?

Yes if you obtained the 80/140 Plus--Heavy Duty Gear Oil.---Keoke

You might be OK to add the 90W to the Hypoid?

 

[Dave Richards]

Na, 'sonly the 90 w replacement....

 

[Dave Russell]

What oil is best for the axle and gear box? My owners manual says W140 for axle, some say W90

If your BN1 has the later hypoid gear axle (after C#221536 with 2.25" wide rear drums) any gear oil SAE rated GL-5 in 80W-90 should work in the axle. The sulfur found in GL-5 oils is a pressure resistant additive which helps protect the hypoid ring & pinion gears which are under a lot of sliding pressure. GL-4 rated oils do not have this high sulfur content. If your axle is the older spiral bevel type, it does not have as high sliding pressures & GL-4 oils should be OK.

For the transmission the factory originally recommended SAE-30 engine oil. Many folks run SAE 20W-50 engine oil in the transmission. A few prefer Red Line MT-90 in the transmission. These are NOT GL-5 rated high sulfur oils. GL-5 oils with high sulfur content are thought to degrade the brass/bronze components found in the transmission/OD's.

Because engine oil & gear oil are viscosity rated at different temperatures, 20w-50 engine oil & 80w-90 gear oil are actually fairly close to the same viscosities.

In reality, if you aren't putting a lot of hard miles on the car, any oils in any location would probably "get by".
D