Yep.

 

You've been a member here since 05 and have over 3k posts and you ask this question now

 

That's what I put in my 2005 SE Fat Boy.
I was using Mobile 1, 75/90 gear oil in the tranny, but read where Mobil doesn't recommend it, so I just use Mobil 1, V-twin in all the holes. I can't tell any difference as far as the transmission shifting, either way it worked fine for me.
Tom

 

Yep... I've always used HD Syn3 in all 3 holes...Was thinking of switching to Mobil or Amsoil just because I'm tired of the MoCo ripping me off....their prices keep going up and up and I don't think their quality is ;-)

 

I'm running Spectro Platinum 90/140 in my tranny. Less 5th gear whine, easy to find neutral.

 

Yes U can, but the Mobil GL 75-90 has additives for gears and I feel it does a better job that the 20-50 Mobil 1 in the tranny.

I switched last yr to Mobil oils and I really like them for our Ind weather..
I did try the Bel-ray Hypoid 85-140 once before going to the Mobil GL, But for me it was too stiff shifting for the first 5 miles or so.

For me the Bel-Ray 85-140 GL was just too heavy for our below 70 temps in the spring and fall, it did alright when the temps were about 85 or above. So in the hotter temp states it'd probably be OK, just not here in IND. Also its not a SYN lube but the dealer said to try it, I did and didn't like the way it shifted at all before she was up to operating temp.

I've use SYN3, Formula+, BEL-RAY and Mobil 1- GL75-90.
IMO, Mobil 1GL 75-90 is the one I like the best and am staying with in the tranny.

 

Think I will go this route. Since we live pretty close and in the same hot/humid climate, which is really tough on engines, I will go this route.