I'm not here to start a holy war, so to avoid that I'm not asking for opinions on why your choice is best

I would however like to know what your choice is for lubricant in your primary case on early Twin Cams.

Harley no longer sells the primary case oil that is referenced in the service manual. The dealership recommends going with their gear oil (80w140).

I've read a number of threads on these forums, but most are 5-7 years old relating to Twin Cams. What is everyone using in 2022?

Thanks! - W

 

Since you asked, B&M TrickShift Conventional.
I won't even comment on the gear oil.

 

Early Twin Cam Primary is the same as EVO.

This year has the old design compensator which was pretty much bulletproof.

There is no reason to get picky about primary oil on this configuration.

ATF works fine, just avoid the new low viscosity types.

20w50 motor oil works fine, but be careful with lower viscosity motor oils, they may contain friction modifiers which will cause clutch slip.

I`m currently using Mercon V ATF in my old Softail primary, but I have never noticed any difference between any of the lubes I have run in that bike over the last 145,000 miles.

 

ATF is hydraulic fluid. There is nothing hydraulic in your primary. better to use motor oil, if you can't find primary fluid at Harley-Davidson or anywhere else. As stated above, beware the friction additives. Just find a good clean 20-50W..

Let the Holy War continue...

 

In the real world, people have used ATF in the primary drive since wet clutches came out in 1984 without issue.

ATF is certainly a lubricant, that is why it works in an automatic transmission, which has many moving parts which must be lubricated.

 

Some people swear they can tell the difference, primary oil , tranny fluid. I been running syn3 for 90. I did have some wear on clutch basket from discs. But I am not sure if that is simply age. I am putting 20w50 back in when I finish with it. Other one at 55k looked ok.

 

Primary chains are very similar to timing chains which are lubricated by engine oil. Have been for almost a century. Clutch plates need merely to be kept wet..nuff said there...

If ATF is your current choice, and its working, then I say stick with it.

Ps. Automatic Transmissions are hydraulically operated. just saying...

 

Bel-Ray gear saver 80w. They also market a primary chain case lubricant. They are exactly the same thing, just different label on bottle so as not to confuse the harley crowd

 

The 80W factor raises my eyebrow a bit. But since the Dealer is recommending it, then I say U can go with it. 20-50w primary oil is what I think Evos were using in the 90's. Gear Oil is for manual transmissions with actual gears inside. I am told that Harleys Transmissions need higher than 80W. More in the 140W range actually. There is a stickiness factor to it that makes rotating gears not fling off so much lubricant. There's another thread on that one...

 

20W-50 motor oil (and the cheap stuff too!) I'm on my second early TC now. The first, my '00 Road Glide, ran nothing but Walmart 'Super Tech '20W-50 for it's entire 170,000 miles. ($2.79 qt )