...used in this garage. Have been wanting to test between M/1 V-T and 75-90 in my big-twin tranny, but have to wait until spring to see results.
Now, what do you guys run in the Sportie trans/primary. I've read till I'm blue in the face, like most of us, and cannot get a good feel for what to run it it except the MoCo stuff. There's got to be a Mobil 1 variation that I can use. What do you guys think?

 

I do the service on my kids' Sporty & have always used Formula+ per the manual. Seems to do a very good job, never had any problems. Shifts fine, clutch engagement is smooth, it's easy to get, and I don't have to wonder if it's the right goo or not...

 

... since I've gotten the Sportster in 9-2010 I've decided to just run the trans/pri stuff the MoCo sells. No complaints whatsoever so far. I'm running Valvoline 10w40 right now (because I ride in the winter when the roads are clear of salt and chemicals,) and to flush it out basically, until I switch it over to M/1. It was pretty dark when I got it. Maybe the previous owner used the 5K service method, and for me, I always to 2500-3000 miles on my bikes. However, I sure do like paying only $5.00 per quart for the Valvoline!!!

 

i've spent plenty of time searching info about transmission oil requirement for hd 5speed and 6speed. But still cant get the clear answer about the A.P.I GL rating. Because like mobil 1 website points out that dont use GL 5 unless recommended by manufacturer and something about corrossion etc. This api GL stuff confuses me.

some use mobil 1 or any 75w90 or 75w140. any one know redline heavy shockproof weight is equivalent to?

any one know which API GL rating for fxdx (5 speed) and 07 ultra (6 speed) tranny oil?

 

Most 75/90 wt gear oils are gl-5. Harleys syn3 as well as amsoils motor oil,has a GL 1 rating. Again I'm guessing that's all that is required by the moco, for a Harley transmission. Alot of people use gear oil that's rated gl-5 ,and you don't hear of any problems with it. Most motor oils have an API symbol and shows the rating on the bottle, but Harley's oil does not. I've read in older manuals they states you should use a SG rated motor oil. I guess you just have to assume their oil carries a SG rating. Other brands state they meet the SG rating or higher, but still don't have an API symbol on the bottle.,,

 

...since I cannot find an answer I like (!!!), which is how some of us feel, I'm going to stick with the MoCo earl in the primary/tranny in the Sportster. I going to stick with the Valvoline for the engine. (Wife gripes about mantainence costs running two bikes).
The big twin is going to stay with Mobile 1 in all three holes. I just cannot, with good conscience, run the 75/90 in the tranny, just because of what M/1 recommends on their website. I did run it (75/90) in my '08 Ultra and had no negative results, nor did I when using Mobile 1 V/T. I give up...

 

I just changed the Engine and Trans oil. I put Mobile 1 70/140 full syn in the trans.

 

At my first oil change I put Mobil 1 V-Twin20W-50 in the trans (500 miles). I immediately heard more noises especially evident in nuetral with the clutch out, but also cruising down the road.

After just a few hundred miles with the 20W-50 in there I changed it again. Went for the big guns in what was probably a little over reaction and put in Mobil 1 75W-140. The noises were definitely quieted and the shifting felt ok but nuetral was a little hard to find.

At the next engine oil change (1400 miles) I left the trans alone.

Then on the last change (4500 miles), just a few days ago, I tried Mobil 1 75W-90. The noises I heard with the 20W-50 remained silenced, the shifting is smoother than with the 75W-140, and nuetral is much easier to find.

So for now it's going to be Mobil 1 75W-90 for me. Maybe in the heat of summer the heavier weight might be better but right now I like the 75W-90.

Everyone has their own experiences and preferences. This post describes mine, along with the rational for making the choice I did.

 

AMSOIL Synthetic 20W-50 Motorcycle Oil is recommended for air or liquid cooled 4-stroke engines. It meets SAE 90, API GL-1 gear oil requirements and is recommended for transmissions and primary chaincases. AMSOIL MCV is recommended for Harley Davidson®, Buell®, KTM, Ducati®, Aprilia®, BMW®, Triumph® and other motorcycles where 15W-50 or 20W-50 engine oils or SAE 90, GL-1 gear oils are used. Not recommended where an API GL-4 or GL-5 gear oil is required.

 

Amsoil severe 75/90