I have a 2009 FLHTC and have been using the Synthetic oil from Harley. Does anyone recommend a better quality synthetic oil for the engine and primary and a quality synthetic oil for the tranny to possibly quiet it down when in fifth gear.

 

Lots of threads in here on those sujects. I use Mobil 1 15/50 in the engine and
Mobil 1 75-90 gear oil in the tranny. It's all personal preference

 

Here we go again! Anyway you can have my recommendation, Mobil 1 in the engine, I prefer the VTwin 20/50, if you want to save a few bucks you can use 15/50 M1 car oil. Redline shockproof heavy in the trans & just about anything in the primary, you don't need synthetic there, I use ATF. There's probably a thousand threads about oil if you do a search, that's why the "Here we go again"

 

My first Bagger was an 09 FLHTC so I know what you are talking about with the 5th gear whine. I bought it from Boswell HD in Nashville. He recommended Belray Gearsaver for the Tranny. I ended up using Amsoil 75/90 in it. Helped with the 5th gear whine. In my 2010 RK and my wife's 2010 SG Trike, I'm using Redline V-twin Transmission oil with shockproof in the Tranny and Redline Primary oil in the Primary. That's about as good as you can buy. I use Mobil1 15/50 in the Engine. JMO

 

 

Mobile Vtwin 20-50. And I can't wait for THAT thread!!

 

You'll get just about as many different replies as repliers. Bottom line is use a quality product and change it on schedule.

 

 

Exact combo that I run in my 2003 Ultra.

 

Same in my 06 Ultra