My tranny is a little noisy on my new RKC. After talking direct with Motor Co. it is a normal characteristic of some trannys, but they gave me a case# anyway.
Talked to dealer's head tech about possibly running Amsoil 75-110 and he advised against it. He said he's had HD reps come down for tranny problems and denied warranty because of fluids other than HD. He also advised to stay away from SYN3 in any hole and stick with FOrmula+ in tranny and primary.
I know that you can run whatever motor oil you choose (Magnussen-Fergusson), so is he bullshitting me or does he have a point? I wouldn't want to blow my 5yr warranty. Don't they have to prove the changes you made were directly responsible for the failure?

 

I'm not 100% sure but I don't believe HD can void your warranty for using another brand of oil - it's illegal. I have run Amsoil 75-110 Severe Gear before and it IS quieter (mainly in 5th) The last two trans changes I went back to Syn3 for convernience.

I bought a qt of 75-110 recenty and plan to go back to it.

 

Yes, you are correct. They have to prove it to deny a warranty claim. If you look around on here a while you'll find that there are a million different opinions about what to run in the tranny. What it boils down to is, it's nothing more than a box full of gears, shafts and bearings. All metal against metal just like any manual transmission. That's what gear oil is designed for so the only thing you really have to consider is what weight oil to run. Colder climates need a lower viscosity, hotter climates need a higher viscosity so it depends on where you live and ride most of the time. A good medium weight would be the 75W90 but if you don't ride much in cold temps you could easily run 75W140 and it would make it run smoother and quieter. As for as what the MOCO or the dealer guy told you. They sell that oil so that's what they want you to buy.

 

As long as the lubricant you use meets the specifications legally you should be OK, but you may have a little hassle getting them to pay if it fails. How bad is the noise, how many miles? What were you using?
Mine was noisier than I liked for the first 6-700 miles, then quieted down some. I switched to SYN3 at the 1000 mile (on the dealers recommendation). The noise was back so I changed it to Formula+ after about 500 miles. Been fine since.

 

Look at Resline vtwin tranny fluid. I used Syn3 then Belray gear oil now Redline it seemss to be the thickest of any of them and the bike never shifted smoother and there is very little tranny noise

 

I used Syn3, amsoil, the HD Formula stuff and I am now using Spectro 6 speed gear lube it has been the best so far.

 

There are a lot of dealers that carry non-harley fluids because they know there is better stuff than what Harley wants to sell. Any good gear oil exceeds manufacturer specifications. You'd never dump engine oil in your cage's tranny, don't do it to your bike. Formula+ is good but Redline or Spectro are way better.

 

Brand New. 450 miles. It has Formula+ in the crankcase right now.
Hopefully it's like yours and quiets down. Should also get better after a Dyno tune, but that's after 1500-2000 miles.

 

I don't know about the rest of you, but the subject - Tranny's and Gear Lube cracks me up.

 

Get your mind out of the gutter