So which one is right for the HD tranny?

 

That's just it, there is no wrong and there is no right. Every one has there favorite oils. I like 75-90 gear lube in tranny, 20-50 in engine and 10-40 in primary. Ask 10 guys get 10 answers, it's your call!!!

 

20/50 royal purple in all 3

 

AMSOIL 20-50 MOTORCYCLE OIL in motor
AMSOIL 10-40 MOTORCYCLE OIL in Primary
AMSOIL 75-90 Heavy Gear in Trans

Been doing for years......never had a problem Be Safe JIM

 

Heavy Shockproof.

 

Redline Heavy Duty Shockproof in the gear box... Doesn't matter too much what you put in the primary. Any decent lubricant will handle that.

 

i run
redline heavy shockproof in the tranny (its the best)
plain jane oil in the primary
syn 3 in the engine

 

Amsoil engine and Trans. Had the dealer do it at 1000 mile service. no problems.

 

A looooong time ago, I heard that a wet-clutch setup needed lubricant that was slippery when under low pressure but not so slippery when under high mechanical pressure (as when our clutch plates are engaged or in a cager's automatic transmission). Is there any truth to that? If so, then shouldn't we use the opposite type of lubricant for babbitt bearings, piston rings, gear teeth, etc. - i.e. still slippery even when under extremely high mechanical pressure (engine oil type)?

 

After doing some research on the forum, and i mean alot of reading, i've decided on Redline Shockproof Heavy for the Trans., Mobile-1 V-twin in the crank, and Castrol GTX 20w-50 in the primary. Seems the popular theory on the primary is it doesn't really matter what you put in there, just want to make sure it doesn't contain too much in the way of "anti-friction" additives so you aren't faced with clutch plate slippage. thats my $0.02 FWIW