in the owners manual for the 02 p650 it says to use the same oil in the front diff. as you put in the engine right? well anyways, if you run synthetic oil in the engine then what are you supposed to run in the front diff?

 

id run the kawiechem stuff, but thats me.

 

Kawichem is for the rear diff. Just run regular oil in the front dif. You can run synthetic, but some guys have said it is too slippery and affects the diff lock. Run regular multiweight oil and you will be fine.

 

Try to use motorcycle engine oil for the front, non detergent as specified. Some have complained about slipping with Synthetic, it has moly and friction modifiers.
I wouldn't use it in front. Just keep good regular clean oil in there.
Kawichem is (Mobile 424), or you can use Universal Tractor Fluid (not hydraulic fluid), for the rear. Amsoil wet brake (tractor fluid) is a good synthetic for the rear.

Mobile Oils
Amzoil