Just had both driven clutches cleaned and since then the sleds do not want to sit still. 99 mxzx440 and a 97 mxz670. I'll start them up and if it is pointed down hill direction it will move. I'll lift the back end up and the track will spin, faster on the 670. I noticed it first on my 440 when I came to an intersection, stopped and then it started to move without giving it any gas. Idle is fine and had both sleds clutches aligned. They ran fine for about 300 miles each after the alignment. Had the clutches cleaned and now cruise control. Any help or suggestions, thanks toi

check belt deflection

your track should be spinning a little when it is off the ground, and for the sled moving when it is pointed down hill?? most sleds will do that, as long as your not goin 30 mph without giving it throttle its fine, you may have to open your secondary a little to slacken your belt off, that should stop them from moving.

my main concern with this problem is belt wear, flat spots. It never did it in the past. The track would not spin when the rear was lifted. The 670 did have new springs installed in the drive and driven clutches. The 440 just had the drive cleaned. I also noticed that the 670 now has a little belt squeel when I am slowing down.

I would have to double check, but am pretty sure that if I lift the back of any of our sleds when warm and idling it will not rotate the track. For that to happen you'd have to have tension on the belt causing the secondary to turn.
The only time I ever had a problem like this was with our 90 Pantera, and it was do to the wrong belt.