Is it safe to say I can put 20w 50w oil in all 3 chambers? engine oil/transmission/primary. I want to change over to Mobil 1 synthetic oil And I notice in the owners manual it looks like all 3 can take the same weight oil. (This is on a 2011 Electa Glide Classic 103 Limited)

 

There are many threads on this, some say motor oil in the motor, gear lube in tranny and trans fluid in primary, you'll have to decide. I didn't make it easy did I. You'll find thoughts on all sides of this. Do a search.

 

I have found that if you use heavy gear oil in the trans., it shifts a lot smoother.

 

yes its safe to do! also there are other choices as well that work as good or better

 

Why in the world with all the better alternatives would anyone even consider putting motor oil in the transmission. Motor oil goes in the motor and transmission oil goes in the transmission and primary oil goes in the primary. Mobil 1 is good for the engine but use Spectro 6 Speed or Redline Shock Proof in the tranny. Use Spectro Heavy Duty Primary in the primary. Don't cut corners to save a buck or two or to make your life easier. I maintain my Deluxe so it will serve me long term.

 

I'd rather have a heavy weight gear oil in the trans.

 

Do what you service manual recommends. Very small needle bearings in transmission, so do not exceed Harley's recommended wt grade. Put Syn 3 in engine and primary (running Moble 1 15-50 in engine since it was on sale at NAPA) Formula + in transmission. Formula + works fine in primary also. Have 40K on mine and was just in primary. Inner primary bearing looked like new. Engine sounds and fill's like new with book compression. Ended up going in primary twice because alternator rotor sheared it's spline and I did not get it quite right first time. (see my album) Yours has a serration which is much stronger.

 

have you ever wondered why hypoid gear oil smells like a goat fart & engine oil doesn't???
It ain't the tranny that smells like that, it's the oil, there is a reason that tranny oil is different!
& NO, fish didn't smell like that until women learned how to swim!

 

Engine: Mobile 1 15W-50 Silver Cap or V-Twin 20W-50
Primary: Mobile 1 4T 10W-40 Motorcycle Oil
Transmission: Mobile 1 75W-90 LS Gear Oil

 

I use mobil1 syn 20/50 in the motor and primary, mobil1 syn 75/90 gear lube in tranny, simple and works.