Can Mobil 1 20w50 be used in the crankcase too?
 

If I do an oil change with Mobil 1 20w50 Vtwin oil, can the same oil be used in the transmission? The Screamin Eagle synthetic oil I have been using can go in both places.

It can but the tranny will like gear oil better. You might want to try the Mobil 1 75/90 or 75/140 gear oil instead.

Yes but a lot of folks on here recommend using gear oil in the transmission. I'm going with the 20w50 Vtwin in all three for simplicity sake. Yeah, I'm lazy but if it doesn't work well, it's not that hard to change. BTW, Kragen has the Mobil 1 20w50 vtwin on sale for $7.99 a quart right now (at least in Cali).

There's a whole section on here for oil related topics: https://www.hdforums.com/forum/oil-a...0&daysprune=-1. Check out the polls if you want to see what others are using. Seems like #1 is Amsoil, #2 Mobil 1 vtwin, #3 Syn3. Although just cause it's popular doesn't mean it's right.

I saw it here in Ohio for $7.99 at Oreilly's autoparts.

Yup. Oreilly's=Kragen=Checkers=Schucks. They're all the same company.

That's where it belongs.

I use the 75/90 in my trans, world of difference on the shifting. So much better than the engine oil.

That's what I did. It does make a great difference.

Kinda what I was thinkin.

Yes, it can be used in both the engine and trans/primary sumps on your Sportster. Some guys use 75w90 gear oil in the trans/primary and some use the 20w50 in there. But you should always use the 20w50 in the engine.

I just used 20w50 in both on my Sportster.

In the big twins, the primary and transmission are separate. A gear lube in the trans is best. The Sportster has a unit construction, the primary and transmission share the same lubricant. I prefer HD Formula Plus in the shared primary/transmission, however the Mobil 1 V-twin is a good choice as well.

The crankcase it the Motor,,, primary is the primary, tranny is the tranny...

crankcase is not the tranny....

but yes U can use Mobil 1 v-twin in all three,,, but as stated above,, in my experience I think that Mobil 1 GL 75-90 is superior to the regualar motor oil and i would recommend using it in the transmission...

This is from Mobil's website, FAQ section:

Sorting Out the Lubes for a Harley-Davidson Dyna Wide Glide:
I have read your question and answers regarding oils in a Harley with separate case, trans, primary. I have been using Mobil 1 V-Twin 20W-50 in all three holes. I am all about optimal product use and performance. Aside from 20-50 V Twin in the engine from what I have read it seems like Mobil 1 Racing 4T 10W-40 for motorcycles would be better in the primary, and 75-90 gear lube would be better in the trans. Is this correct? 2002 Harley-Davidson Dyna Wide Glide. Also I see you have a 75-140 gear lube. The manual does not specify weights of oil to use and it's one of Harley's marketing schemes to make you buy their oil.-- Michael Lawton, Howell, NJhttp://www.mobiloil.com/USA-English/...ges/spacer.gif

Answer: We recommend that you keep doing what you're doing and use Mobil 1 V-Twin 20W-50 in all three applications. By using a premium synthetic like Mobil 1 you are already using a high performance lubricant in your bike. Using Mobil 1 Racing 4T 10W-40 in your primary is an option but we would not recommend the use of an API GL-5 gear oil in your transmission.

well that is interesting, wonder what all those guys that use the GL in thier tranny are going to have to say about that:icon_munching:

Ive been running Mobile 1 75w90 in my trans for years with no problems what so ever....if anything it has made it smoother and quieter.

Now..............Sportsters.....I would not run a gear lube in the primary/trans of a Sportster. Your clutch will not like it and it will slip. Ive experimented on Twin Cams and evos and have had some slippage when runnin the gear lube in the primary. Stick with HDs Sport Trans fluid.

If your a good welder I could get into how you can separate the trans from the primary on a Sportster, drill and tap the case for fill and drain plugs and your all set up to run an open primary belt.

I didn't think you were supposed to use the 20-50 syn in the big twin primary.. clutch slippage and all that..

20w50 is fine in the primary..........gear lube is bad

My 2010 Street Glide came from the factory with Syn 3 in the engine, trans, and primary.

I find it interesting that MOCO recommends Syn 3 in all three locations, must mean the gearbox and primary were designed to be used with synthetic 20-50?

first and only service I had done at dealer the said they put the same syn in all three holes. now I have been using 20/50 mobil 1 in the tran and engine ever since and that is 50 thou miles no problem.. I use a cheap reg. oil in the primary and so far so good..

I switched to Mobil 1 75w90 30k ago and have been happier with it. Tranny is butter smooth now.

Just curious.... would you have switched to the GL in the transmission if you had read that Mobil says they don't recommend it? I know allot of guys on here use it in the tranny and i suspect allot of guys on here got that recommendation from others on this site. I wonder how many of them would do the same after reading the post in this thread where the manufacturer of the product doesn't recommend using it???????:icon_mrgreen:

i run 75/90 in the trans. quieted down the trans and shifts like butter.

My official Harley Service Manual specifies "Formula+ Transmission and Primary Chain Lubricant (Part No. 99851-05) or Syn3 20W50 Oil" for both the Transmission and Primary. I haven't been able to find any specs yet on the Formula+ so I don't know how it compares with the Mobil 1 75w90 gear oil. I have Syn3 in all 3 holes right now but I'm definitely ready to try something different in the transmission if it'll help it shift a little smoother and quieter.

I am definetly no oil expert and quite frankly don't no much at all about it. If you like what you use fine, ain't my bike.

But let me ask you this, wouldn't the thicker 75/90 take longer to flow through the gears until it gets up to temp? wouldn't that cause damage because it doesn't flow as well as the 20/50? i am just curious because i myself want to change to the Mobil 1 and just trying to get info.

Well....
Wanting to raise the BS flag, I went to Mobil1's website in search of info because I've been using their 75/90 for 4 years now.
And I came up with this. :icon_frown:

I went with the Mobil1 20w50 vtwin for the oil and I went with the Mobil1 75/90 gear oil for the trans. I have riden it for about 30 miles so far and it shifts much smoother and the clutch is easier to pull. I can't wait for summer to see how much cooler the motor will run.

Just when I thought I had the proper lubricants for my new bike figured out this comes up. Back to the drawing boards I suppose.

Michael

There is no oil pump in a trans. The gears distribute the lube. IMO the thicker oil clings better to the gears. The damage is not going to come from a cold trans....it wears when the trans is hotter than hell and you have engine oil in it. Its a gear box....I use gear lube in it and I will continue to do so just like I have since 1992 when I bought my first HD at the age of 18. Ive logged alot of miles since then with no trans problems.......ever!

Dude...they dont recommend API GL-5 in your trans.......that doesnt mean you cant run 75w90 gear lube in a different category. Honestly I just went and looked and my Mobile 1 75w90 says it meets or exceeds the GL-5 category. Ive been running it for a long time and havent seen any of my "yellow" metals fall apart. There are literally thousands of people running this stuff in their HDs and how many do you see on these forums complaining of their bushings getting ate up because of lube? 0....thats right.

Yes...you can put cooking oil in there too, but why? It's a tranny so use what's recommended (GO). I recommend Spectro - spendy, but their 6-speed GO really quieted my 09 FLHX whine.

Same here

20W-50 motor oil is thicker than 75W-90 gear oil. Gear oil and engine oil use two different viscosity rating systems.

http://www.synlube.com/images/viscosity_table_2.jpg

Just because something doesn't damage something else quickly doesn't mean damage isn't being done. It could be that an engine which would have lasted 165,000 miles instead croaks at 157,000 miles. That's 8,000 miles lost, but the owner will never know because he'll chalk it up to "it was my engine's time to go."

:icon_mrgreen:

While I agree with you as I'm also using the stuff - it did raise an eyebrow that the manufacture of said oil doesn't recommend using it in the tranny...

I have been searching for what HD requierments are as far as API GL ratings are and have found nothing. Are the oil companies warnings specific to HD or are they general warnings in regard to transmissions made with softer yellow metal parts? Does HD use these softer metals in their newer transmissions?

Michael

Im not gonna lose sleep over it. I just talked to a local mechanic that has forgot more about Harleys than I will ever know and he kinda laughed at it. He fills alot of trannys up every week with what else......Mobile 1 Synthetic 75w90 gear lube. So until he finds something better to use...im stickin with it.

We arent talkin about engines though.....we are talkin gear boxes. But i get your drift. I wish I could get 160,000 miles out of a Harley without major work.

I have yet to hear about anyone damaging their trans with Mobil 1 gear oil.

The M1 gear lube is not good for your Sportster Booey420. Why?
1)Not hypoid gears; the reason GL-5 oil was developed.
2)There are a lot small yellow metal components in the transmission/primary unit that the gear oil WILL eat through, it's just a matter of time.
3)It is not JASO-MA rated, which means it is not good for your clutch and it is not recommended for wet clutch operations. Some argue that since it is used on LS differentials that this is okay, but those are not the same type of clutch as on our bikes. They use different materials and serve a much different function.

I personally use M1 20W-50 in all compartments. You can use the M1 15W-50 auto oil in the engine only as well. If you are set on gear oil for your primary/trans. I would use a GL-4 over a GL-5, but don't recommend it.

The warnings are to transmissions with yellow metal. If it is only a transmission like in Big Twins (NOT Sportsters), then a GL-5 is acceptable. I'm not sure of any yellow metal components in HD transmisssions for the BTs(bearings, rivets, pins), which would degrade with the use of a GL-5, but it is suitable for no-yellow-metal transmissions alone. 75W-90 or 75W-140 is good.

That being said, the MoCo keeps a close guard on it's recommended oils (like Formula+) so no one really knows what's in there. The best bet is to use purpose made oils in the correct weight.

Engine: 20W-50 engine oil (since HDs have independent engine sumps)
Primary: 10W-40, chaincase oil is ideal, be aware of wet clutch operation
Transmission: 75W-90 gear oil, anti-shear additives, low sulfur content
Prim/Trans (Sportster): SAE 20W-50, take note of the wet clutch and primary operation, this is why a gear oil is not good for this unit construction sump