Went riding with some buddies this weekend and my 96' sportsman was doing something strange. The 4 wheel drive would work most of the time at slow speed but when going faster it would not engage. Then while the back tires were spinning the quad would shake real bad unless I would give it full throttle. Odd thing is is that it would not shake at all on dry pavement. I can put it on ice and make the back tires spin without the clutch cover and really dont see anything wrong. Sorry, but really hard to explain.

 

Check you drive shaft (from trans to front differental) Just repaced two.Both were stripped where they connect to transmission..