Is it ok to use castrol full syn. 5w40 in the motor. I used the non-motorcycle type oil. Also I bought the semi-syn. 80 w90 for the front and rear diff. Can I use this oil in the diff. and be safe? Thanks

 

yes

 

If it has the star burst symbol on the container....I wouldnt. That means it has moly, and your honda has a wet clutch, and moly and wet clutches dont work well with each other.
I think the owners manual spells out what fluid to use in the diffs. I think its gl4 or 5. If the stuff you bought has the correct rateing, and the proper viscosity...its good to use.

 

A great article about why you DON'T want to run "car" oils: http://www.thumperfaq.com/oil.htm

What does your owner's manual recommend you run???? I'm not sure what these Honda automatics will accept, but your transmission runs by pumping pistons around using oil pressure, so you darn well don't want to be using the wrong thing!!!! Plus you have at least one clutch in there, so you will want to stay away from the friction modifiers found in car oils.

In general, one cannot go to far wrong picking an API SG/JASO MA motorcycle specific oil......and I'm betting that's what your owner's manual will tell you. If you can't figure out what else to run, just use Honda HP4.

Just for the record I run Maxima Extra, an ester based synthetic in everything (including both the engine and trans sides of my 450R).

As for the diff, again what does your owner's manual call for??????

 

I was unaware the Rancher AT had a wet clutch....
i know it has a hydrostatic swash plate. but no clutches that i know of.
i use rotella fully syn in mine and 2200 miles later she still works great. :-)

HR

 

The oil pump has a wet centrifical clutch on the input side. That way it can idle in "gear", without the pump driving anything.