final drive oil and drive moly grease

roadrider

roadrider

Joined
Aug 16, 2008
Messages
70
Location
goldendale wa.
if i understand the design of the final drive it has 2 holes in it, which allows final drive oil to enter the area where the drive shaft splines are located and that oil to mix with the moly grease on the the splines. if that is correct. will that oil return to the final drive with some of the moly grease mixed in with it ?
another question. the engine oil is used to lube the transmission bearings/gears it is a 10/40 weight. that oil gets hot and dirty. but in the final drive 80-90 oil is required which is used to lube the bearing/gears. that oil does not get as hot or dirty. don't the gears in either area have the similar pressure/loads on them ? so why the different weight oils ? not wanting a big debate, just curious.
 
No mixing goes on, the oil stays put, or should, just like the moly should.
The diff uses diff oil because it can, it only has itself to look after. No compromise required.
The gears are lubed with the same engine oil because there's no choice, that's where Honda put them, but motorcycle oil is designed to work with the gears too and the properties allow a happy marriage.
But you highlight the importance of keeping to the service schedule, bike oil works hard.
So you're good to go.
Upt'North.

No debate, :doh1:, an oil thread in a pandemic. :hat2:.
 
yes it has the 2 holes but they don't really mix. You could even say not at all. Those holes have been in the pinion cup on many models of Honda's.

Don't lay your bare hand on that rear pumpkin after a good ride on a warm day. It gets plenty hot.
 
Bush said:
Different animals entirely, because the gear types are different. It's a good idea to use synthetic hypoid in the final drive too.
Click to expand...
The main oil difference isn't due to different gear type or loading but is due to the very different lubrication systems. One is pressure and the other is splash or spray.

Pressure lubrication is a process where an oil pump precisely distributes oil to transmission/ engine/ cooler/ filter. The viscosity of the oil is not as critical as with a splash lube system.

In a splash system the oil is moved from a trough by rotating dippers or gears. The type of oil used and its viscosity is very important in a splash lube system; the oil must be thick enough to provide sufficient lubrication and cling to the dippers, but not so viscous that it heats up as it is churned about in the oil trough.
 
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It is my understanding that the loading on the gear teeth is different for the right angle drive in the pumpkin compared to straight cut gears in the transmission. If you read the service manual, the gears in the aft must be shimmed to get the proper engagement while in the transmission, we only shim to assure that one gear fully mates with the one below it. Engagement is determined by the location of the gears' shafts.

BTW, if your final drive has the vent at 12 o'clock, and you turn the bike upside down, gear oil will leak out. No bench pressing the bike to show off! :rofl1:
 
roadrider said:
don't the gears in either area have the similar pressure/loads on them ?
Click to expand...
TPadden said:
The main oil difference isn't due to different gear type or loading but is due to the very different lubrication systems. One is pressure and the other is splash or spray.

Pressure lubrication is a process where an oil pump precisely distributes oil to transmission/ engine/ cooler/ filter. The viscosity of the oil is not as critical as with a splash lube system.

In a splash system the oil is moved from a trough by rotating dippers or gears. The type of oil used and its viscosity is very important in a splash lube system; the oil must be thick enough to provide sufficient lubrication and cling to the dippers, but not so viscous that it heats up as it is churned about in the oil trough.
Click to expand...

Regardless of your theory, hypoid and motor oils are not the same and have different additives and properties for different reasons.

Don't Forget the Gear Oil

High-quality gear oil must lubricate, cool and protect geared systems. It must also carry damaging wear debris away from contact zones and muffle the sound of gear operation.
www.amsoil.com www.amsoil.com
 
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