Mobil One Oil

[Jerrym]

Which is the best to use in the transmission and rear drive Mobil Synthetic Gear Lub 75W-90 or 75W-140? I had always used 75W-90 but I picked up by mistake 75W-140. Is this OK to use?

[amarider]

Yes - That's the same weight as the BMW Syn.

[Daman858]

Don't ya just love the smell of that stuff? The gear oil, that is.

[Hilton]

Interesting question. '99 to '04 CD has 90w for the trans and rear drive. '04 and latter CD has 90w for the trans but 75w140 for the rear drive. Still waiting on an answer from service guy here. As I change both oils way more often than needed, probably not a big deal, but wouldn't the heavier weight have more cushioning effect for a given temp? (gear teeth as opposed to our infamous bearing) From my straw poll, service centres fill both with 80w90.

[TimVipond]

Page 75 in my 2006 K1200LT manual says Brand-name hypoid gear oil, API class GL 5. and Viscosity class Castrol EPX 90 or SAE 90 API, so I would think the Mobil Synthetic Gear Lube 75W-90 would be the preferred of the two, but I wouldn't sweat it if you had already put the 75W140 in. I searched on this board and it seems alot of riders use it. You might experience a very slight loss of horsepower and gas mileage. I'd change it after 6,000 miles and put in the 75W90. But you might contact BMWNA at Motorcycles 1-800-345-4BMW to make sure.


From Mobil1.com:

Typical Properties

Mobil 1 Synthetic Gear Lubricant LS

SAE Grade 75W-90
Viscosity, ASTM D 445
cSt @ 40ºC 106
cst @ 100ºC 15.2
Viscosity Index, ASTM D 2270 150
Pour Point, ºC, ASTM D 97 -46
Flash Point, ºC, ASTM D 92 175
Density@15C kg/l, ASTM D 4052 0.859


Typical Properties

Mobil 1 Synthetic Gear Lubricant LS

SAE Grade 75W-140
Viscosity, ASTM D 445
cSt @ 40ºC 179
cst @ 100ºC 25.3
Viscosity Index, ASTM D 2270 175
Pour Point, ºC, ASTM D 97 -51
Flash Point, ºC, ASTM D 92 221
Density @ 15ºC kg/l, ASTM D 4052 0.863