HD 80w140 gear oil
Club Member
Joined: Mar 2009
Posts: 66,106
Likes: 51,387
From: Niles Canyon Ca.
Factory service manual for shovelheads recommended straight 50 or 60wt motor oil. I haven't had the transfer issues with my 17 RK yet but if it comes up I'm going old school on it, 50wt been working fine in my 4 speeds for decades.
Tourer
Joined: Dec 2006
Posts: 299
Likes: 121
From: Potomac, Md.
Is it just me, or has any body else noticed, that Syn3 can be run in all three holes... Or basically 20-50, and yet the conversation continues about this is better than that. I think Harley has once again won the Psy-ops campaign. Just my opinion. CSM-H
Cruiser
Joined: Aug 2014
Posts: 169
Likes: 30
From: Gulf Harbors/Woodlands, FL
I switched mine to the HD Gear lube on the first service, been running it about 500+ miles now. Shifting is buttery smooth. Transmission has a little less whine. I'm in Minnesota where the temperature highs are still in the mid 50's at best. The 2019 FLHTK seems to really like it. In previous bikes 2016 FlHTK , 2014 Dyna Street Bob and 2014 Street Glide Special, I only used Formula + as every bike's primary sounded like a bucket of bolts on anything else.
Ultimate HDF Member
Joined: Apr 2006
Posts: 6,913
Likes: 87
From:
I run Syn3 in all three holes with no problems in my 2018 M8 114 and in my older '07 Road King TC 96.
Seasoned HDF Member
Joined: Feb 2008
Posts: 22,999
Likes: 11,439
I put the 80W-140 gear lube in primary this morning. The lube in the primary had 9,000 miles on it and the bike has 25,000. I had the lube here my plan was to open primary and check for any transfer . There was none. Decided to put the Gear oil in. Time will tell.
Road Warrior
Joined: Sep 2016
Posts: 1,887
Likes: 1,059
From: SE Washington
Is 80-140 recommended for the primary? Thought it was for the transmission only.
Road Warrior
Joined: Sep 2016
Posts: 1,887
Likes: 1,059
From: SE Washington
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Seasoned HDF Member
Joined: Oct 2014
Posts: 5,022
Likes: 2,352
From: Camp Lejeune, NC
I was at the dealer this morning picking up some bolts. They had this fluid at the counter so I grabbed two quarts. Swapped out the Redline Shockproof and Formula + I had in the trans and primary respectively. Just wanna experiment to see if it feels any better having a gear oil in the primary and figured why not try it in the trans too. Riding up to Buffalo, NY on Monday to visit a buddy so Ill have plenty of road time to review it. Will post what I think for those who are curious.
Intermediate
Joined: Apr 2019
Posts: 39
Likes: 11
From: Santa Clarita, CA
My dealer installed it in the trans and primary during my 1000 mile service. It's about $20 a quart but he gave me a credit of $10 a quart for the other trans and primary oil, so it wasn't too costly.