It is time for my 1000 mile oil change. I am going synthetic (my dealer says it is ok at this time). The dealer claims you can use the same HD Syn3 oil in the enigine, transmission, and the chaincase. I know some people have been using combinations of Mobil 1 synthetic 20w50 for Engine, Mobil 1 75w90 Syn gear oil for the trasmission, and HD Formula + Transmission and Primary Lub for the Chaincase. Now for the multiple choice questions.

1- Can I use Mobil 1 Syn 20w50 for all three?
2- Can I use Mobil 1 Syn 20w50 for engine, Mobil 1 75w90 for Transmission, and Mobil 1 75w90 for Chaincase
3- Can I use Mobil 1 Syn 20w50 for engine, Mobil 1 Syn 20w50 for Transmission, and Mobil 1 75w90 for Chaincase
4- Can I use Mobil 1 Syn 20w50 for engine, Mobil 1 Syn 75w90 for Transmission, and Mobil 1 Syn 20w50 for Chaincase
4- all of the above.

Thanks.

 

4...

I use AMSOIL 20w50 for the engine & primary & 75W90 in the trans

 

Based on everything I have read, I would suggest choice #4. is the best of your options. I personally have had great results in my 2007 Street Glide with Amsoil 20W50 in the motor, Harleys chaincase lube in the chaincase (I don't remember the name of it) and Redline Heavy Duty Shockproof in the tranny.
I am sure your Mobil 1 choice #4 will be a great choice as well.
Ride safe and enjoy!

 

I would definitly throw the heavier wt in the tranny... helps with the knocking sound on shifting... and overall -better coating on the gears...[sm=bounceybounce.gif]

 

same here or try this

amsoil 20w50 for engine
amsoil atf for primary
amsoil 75w90 for trans

 

I put Mobile 1, V Twin 20w50 in the engine and primary. Mobile 1 75w90 gear lube in the tranny.
When you say Mobile 1 20W50, I assume you mean the V twin version. In the regular Mobil 1, I think the closest you can get is 15W50.
Tom

 

 

Mobil 1 V Twin 20w50 Engine
Mobil 1 75w90 transmission
Formula + for Primary.....

 

Why wouldn't you use what HD recommends? Are you trying to save money? You know the SYN3 will work.

 

Just go with the Red Line Big Twin 20W50 PowerPack at Racer Supply. I think they are still a sponsor here and you can get a few % off if you tell them you learned about the deal here!

I used this in my FXSTD-SE and it ran cooler and quieter....shifted smoother also, and all I had to do was think about neutral, and the green light would come on!

This is a super deal