Found this over on ECStuning.com. I read some time ago that the transfer case on 535Xi cars contain approx. 1 liter of fluid. That in and of itself makes me nervous, so when should this be serviced? Here's the link to the kit that is offered and also available is a nifty tool which can be used to service transmission, differential, etc.

http://www.ecstuning.com/BMW-E60-535...se_ServiceKit/

 

I'd change transfercase fluid [and both front and rear diff fluids] at 60K miles.

 

i've got some time...thanks for your reply.

 

don't care how many miles you have on the car, the time to change is now. the yards hoard those things like gold and I was lucky to find one used for less than $1000 when a friends went bad.

 

thanks allen