I would like to convert my 05 King to Synthetic. I'm having trouble with the rear differential fluid. Mobile 424 does not cross over very easy. Confused about the tranny oil as well. Lastly, which weight of engine oil are you using in synthetic? I will be using Amsoil.

 

amsoil make a complete line of quad sins. go to my url / my website at the bottom it has a link to amsoil. they started making sins. for jets in 1972 and there temps for oils breakdown are about double everyone elses. but pricy , but well worth it , i use it and the different is crazy! ps!!! no friction modifiers / so no clutch slip

 

amsoil ATH = Mobil 424
Hope this helps