2012 Rancher 420 4wd

Over the weekend, our oldest son had my wife's 420 in a shallow pond ( not even up to the tailpipe). He got out in the middle and got stuck. Not sure what he did, but it started slipping while it was out there. We got it out and back to the house. Now, it will pull itself under easy throttle, but when it's given more it stops, and makes a noise similar to a chain coming off a sprocket and spinning fast at first then winds down. Give it easy throttle and it goes back to pulling and repeats. It does it in both 2 and 4wd. Absolutely no popping noises coming from either differential. Any chance the clutch could just need adjusting??