Not true, use a gear lube in the trans, not an engine oil. Mobil 1 75/90 or redline shockproof heavy are good here, also the HD primary oil works well and has for many centuries without the added cost of syn. It also gives a better feel to the clutch

 

vulhalla, if you use SYN3, you can use it in all 3 holes. If you use Amsoil 20-50, you can use it in all 3 holes. What oil were you going to use?

 

I used syn3 in all 3 holes, so I guess I'm ok huh? maybe I have to adjust the clutch. Its just going in there for the first time and second guessing myself wondering if Im doing it right.
I guess if I follow the DIY section on the easy clutch adjustment and my service manual hopefully I should be all set. I just dont want to screw anything up.

 

There have been reported issues at dealers with the syn 3 in the transmission with the bearings going out prematurely and damage to internal transmission parts . It's your choice as to what you want to use. A gear lube will give you better lubrication in the trans over an engine oil any day. Make an educated selection of lubrication based on known issues and not just on what others use including myself .JMHO

 

Vuhalla,

To clear this up for you, HD says you can use Syn 3 in all 3 holes. Markcuda and others on this board are doing so, and Markcuda with his 4 gozillion miles has had no problems to date...and I'm guessing he probably has more miles than you will ever put on your bike, though I may be wrong.

There have been reported problems with bearings in the Tranny as TCSTD has said...so there are many (to be fair, I'm one of them) that thinks you should use gear oil in the tranny due to it's gear intensive environment. 75W 90 is about the same viscosity as the 15W50.

To further muddy the water, Mobile1 and Redline are TRUE synthetic, while Syn3 is not a fully synthetic oil.

Hope this helps.

Mac

 

I don't know what I'm talking about here, but if the bearings are failing what does it have to do with using gear oil? It seems if the gears were failing then gear oil should be recommended. It seems that bearings SHOULD be more tolerant of different oils. Don't you have bearings both in the engine and the transmission not to mention other places? Does the transmission have special bearings that require gear lubrication? It seems like defective bearings to me. But again, I really don't know what I'm talking about. Anybody care to explain?

 

1200

It has to do with the shear factor of the make up of the oil itself. The gear lube does not shear (can't recall the exact term ) an easily as the syn 3 will ,thus giving better protection. True that you have bearings in the engine but you do not have the added abuse of the gears that are in the trans.

 

I have talked to more than a few Mechanics who say DO NOT use syn three in the tranny.
If someone chooses to run it I guess it's there money to do what they want with. I personally don't use SYN 3 in anything. I remember when the MOCO told us all that SYN should not be used in HD motors then all of a sudden they came out with there brand and now it's ok to use it. I don't understand why people would pay more money for Syn 3 to put in there trannys when there are so many other quality products around for less money,and IMO do a better job. Products Like mobil1 75-90, Redline shock proof heavy that are specifically designed for trannys. I have always used Mobil1 v twin in my Motor after the breakin. I have some friends that used SYN 3 in there motors and then tried Mobil 1 vtwin. There responces to me were, there never going back to SYN 3. I also don't use motor oil in the rear of my truck either for the same reason. Just my .02 RK101

 

So I guess the most popular general consensus is Mobile 1 for v-twins in the oil and primary and Mobile redline shockproof in the tranny?

 

Redline Shockproof Heavy isn't a Mobil brand, it's Redline. Google myoilshop.com and you can buy it on-line.