Does the limited slip diff in our u600 require friction modifier? I was planning to change the fluids with Lucas and it is supposed to work with limited slip. I actually run it in my Jeep with limited slip.

[2015 Z Force 800 53/Trail EPS]

Anything with friction plates such as it has requires a friction modifier so that it evacuates from the surface areas as needed. With conventionals it may not be necessary but with synthetics...probably so. If it states it is rated for limited slips, it's probably already got what it needs.