I have some problems with the 4wd slipping on the Grizz. It's a 2006 660 with 2600miles (all stock) Sometimes while in 4wd the rear doesn't push. I was out at Jim's Creek a couple weeks ago and had it in 4wd with diff lock engaged and, on the ice, only the left side was spinning. The right side (front and back) did nothing. The problem is random. It doesn't happen all the time and doesn't last that long. It just kind of comes and goes. It's not always the same side (L or R) or (F or B).
I'm not a mechanic by any means, but I bought the book and want to learn to fix this myself, but I don't know what I'm looking for yet. Any help?