I recently purchased a 2012 Street Glide. I am getting ready to change the fluids but not sure exactly what fluids to use. I know that HD recommends SYN3 in the engine, tranny, and primary drive but I have heard many mixed views about SE SYN3 that HD recommends. Which fluids will run the engine cooler and will quiet down the transmission?

 

I switched to HD SYN3 in all 3 at 1000 miles. Works fine as far as I am concerned.

 

 

You seem to sound like a rookie and this of course will become an oil thread on all the favorites. However, use Harley's engineering is the safest way. I can only assume the reference to the transmission is the clack going into low from neutral. That is just the spinning gear stopping by the drive dogs. All the gears are meshed, so that is not gear teeth. There are some small needle bearings in there. Do not put too heavy an oil in it. That clack and the one shifting is normal for a Harley. If you want to lessen the that first clack, PM me and I will tell you how I do. It will stop it apx 90% of the time.

 

Lots of threads out here on this topic...here are a few I'd started/been watching.

Ignore the hatters complaining that this topic has been beaten to death (although I agree). A simple search on the topic will revail alot of threads relating to the topic.


https://www.hdforums.com/forum/oil-and-oil-related-topics/752555-primary-oil.html

https://www.hdforums.com/forum/touring-models/788372-redline-primary-oil-anyone-using.html

https://www.hdforums.com/forum/oil-and-oil-related-topics/748948-transimission-fluid.html

I'm using Mobil 1 VTwin syn in engine and Redline in the primary and tranny. There's alot of science that has gone into this...I've neen told to not switch to Syn until the engine in fully broken in - ~2,500 miles or so. Also there are great threads here on proper breaking methods for an engine...and there are ALOT of opinions as to how to properly do it. Just pick a method and stick with it.

 

Mobile 1 V-twin - all 3 holes.

 

I use the fluids as recommended in the manual- for each of my bikes.

so the new bikes get a synthetic, the older bikes a conventional multigrade.

The twin cam gets syn3 motor oil, primary+ for the primary case and transmission.

I pay a little more for the stuff at the dealer, as the other products seem to come and go

( fluids of different types may not mix well, the primary will retain about 4 oz of the current lube on a change...)

The twin cams are engineered to take advantage of the synthetic oils ( better castings/ machining of the mating surfaces) and the ability of the syn to take high heat.
The twin cam is the first H-D motor to spray oil at the bottoms of the pistons to aid cooling. a conventional oil might shear and turn to coke


NO mechanical problem was ever solved by a fluid or additive, and some of the stuff out there is "snake oil" ( remember Slick 50? the most advertised product, sold hundreds of millions of dollars of useless goo)

Mike

 

mobil 20-50 v-twin in motor and primary, redline heavy shockproof in trans,done deal

 

If you wanna quiet things down, I sure wouldn't use synthetic. I also know a couple people that had gasket weeping issues with syn. And, I would worry about "bearing skate".

Davidsons & other vehicles have been running on dino oil for over 100 years. I see no reason to change.

And, I love that clunk when shifting into gear. Reminds me that it's a Harley & that it is really in gear, not like a metrics wimpy little "snik"!

 

gear oil in the tranny, motor oil in the engine, and just about any oil in the primary, but I'd stay away from synthetics there, waste of $$. ATF works really well, B&M TrickShift, for example

Depending on where you live & how much you ride and when, the MOCO has a nice table of recommended oil weights in your owner's manual. 20/50 is not always the best choice....