Ryker gearbox oil

[Overfill]

Ok folks,
I am looking at the lubricant recommendations for the Can-Am Ryker gearbox (NOT the final drive; NOT the engine oil):

I have 3 thoughts given all that they allow.
1) The gearbox does not need GL-5. This is because they permit the use of an API SN engine oil.
2) The use of a API SN 5w-40 oil will shear to a 30 (gear 85), should I worry about getting a 50 / 140 weight?
3) Should I be leery of an off the shelf GL-5 (where the primary EP is sulfurized olefins)? Would the sulfurized olefins attack any bronze thrust bushing/washer, or overcome the metal deactivators?

 

[BusyLittleShop]

The difference between a API SN 40 grade sheared to API SN 30 grade is visually this degree difference in flow... What Can Am is permitting is a choice during times of limited supply because either oil will meet and exceed your expectations... given their blessings there is no good reason to worry...

 

[troop]

I was going to suggest a quart of Rotella T5 5w40, but it's tough to find 1 quart containers anymore. And using only 10-13 ounces per drain/fill, a gallon jug is not practical. Heck, just go to the dealer and buy a quart of XPS 5w40. They now have it in full synthetic if that's an option...

 

[Overfill]

My current solution is to get some Mobil 1 V-twin, since it is GL-4 and viscosity compliant for my climate (warm). It's also very shear resistant and has good antifoaming performance. The other option I was considering was UTTF, which is GL-4 albeit a 30 / 85 weight.

 

[EvoMan]

I think running the Mobil 1 V-Twin will serve you well. There are lots of guys running that in their Harley transmissions without issue.

I was using that in one of my Harley’s until I switched over to HPL V-Twin 75W-140 transmission oil.

 

[repairman54]

A marine oil is another possibility since it sees a lot of constant high rpm / shearing of the oil.

 

[Overfill]

If gears and bearings operate in the boundary lubrication regime, then what purposeful difference is it to choose an 85 vs 90 vs 110 vs 140? Sling? @OVERKILL @RDMgr
Again, no clutches, (it seems no copper or bronze,) and not talking about "cold" temps.

harkens this thread: https://bobistheoilguy.com/forums/threads/importance-of-gear-oil-viscosity.380070/

 

[OVERKILL]

If gears and bearings operate in the boundary lubrication regime, then what purposeful difference is it to choose an 85 vs 90 vs 110 vs 140? Sling? @OVERKILL @RDMgr
Again, no clutches, (it seems no copper or bronze,) and not talking about "cold" temps.

harkens this thread: https://bobistheoilguy.com/forums/threads/importance-of-gear-oil-viscosity.380070/

I would think that if you are worried about EP performance you'd want to run a dedicated gear lube, which has EP additives in it, unlike engine oil, which doesn't.

I think different parts of a gearbox run in different lubrication regimes, in the case of a differential, I'd assume the ring and pinion are operating in boundary (and need EP), while roller bearings may operate more in mixed, in which case viscosity becomes more relevant.