Damn i need a owners repair manual, primary?
#11
01-04-2010, 10:32 PM
Tourer
Just drain out the old fluid and install 1 quart of 'whatever' through the primary inspection cover.
No need to remove the derby cover.
For what it's worth, myself and most of the guys I know that own Sportsters use API GL-5 rated Mobil 1 75w90 Gear Lube in the combination primary/tranny. I don't use regular 'motor oil' in the manual transmissions on my cars and trucks, and I also don't use it in the manual transmissions on my Harleys.
Before you say that 75W90 is too 'thick' just remember that the viscosity of motor oils and gear lubes are calculated differently. A 75W90 gear lube has about the same thickness (viscosity) as a 20W50 motor oil. Many gear lubes (such as Mobil 1 75W90) have a low enough moly content that you won't have to worry about possible wet clutch issues down the road.
No need to remove the derby cover.
For what it's worth, myself and most of the guys I know that own Sportsters use API GL-5 rated Mobil 1 75w90 Gear Lube in the combination primary/tranny. I don't use regular 'motor oil' in the manual transmissions on my cars and trucks, and I also don't use it in the manual transmissions on my Harleys.
Before you say that 75W90 is too 'thick' just remember that the viscosity of motor oils and gear lubes are calculated differently. A 75W90 gear lube has about the same thickness (viscosity) as a 20W50 motor oil. Many gear lubes (such as Mobil 1 75W90) have a low enough moly content that you won't have to worry about possible wet clutch issues down the road.
#12
01-04-2010, 10:36 PM
Ultimate HDF Member
You can run whatever you want, but I'm sure not comfortable running a AFT fluid in the gearset of a manual transmission... 
I'm sure that you realize the Sportsters use the same fluid to provide lubrication for both the primary and the transmission, unlike the Big Twin's in which you can use a different fluid for each.
For what it's worth, on my Big Twins I run nothing but regular Rotella T 15W40 in the primary for 'splash lubing' the chain and clutch pack.
Even though I don't run the Rotella in transmissions, I would be more comfortable using it for protecting gearsets over any ATF fluid....
But opinions vary so everyone is free to use whatever they want.... Below is what I run in my Sportster, but each to their own.
I'm sure that you realize the Sportsters use the same fluid to provide lubrication for both the primary and the transmission, unlike the Big Twin's in which you can use a different fluid for each.
For what it's worth, on my Big Twins I run nothing but regular Rotella T 15W40 in the primary for 'splash lubing' the chain and clutch pack.
Even though I don't run the Rotella in transmissions, I would be more comfortable using it for protecting gearsets over any ATF fluid....
But opinions vary so everyone is free to use whatever they want.... Below is what I run in my Sportster, but each to their own.
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