Hey everyone, new to the forum here. I've got a 1999 Polaris Sportsman 335 4x4. This past winter i went through a pretty deep water hole. No mud just deep water. It ended up getting stuck and it was under water almost to the top of the motor for about 15 minutes until i could get it pulled out. Afterwards, the belt was slipping due to water getting in there. It slipped some while my buddy was driving and ended up shredding. Took it home and ordered a new belt and gasket for the casing, all new rear end bushings, and two new rear axles. All bushings and u joints were shot in the rear. Replaced all these parts when they came in and also changed the oil and oil filter. After doing this over the course of about a month i took it for a ride. It rode terrible, i couldnt hardly go over 15mph because it was hopping and jumping around so bad. I decided to take it to a shop i had been to before. He had it forever and changed the fluids out with new in the transmission/gearbox and decided that a chain needed to be replaced in the transmission. I dont know too much about the transmission/gear boxes on these ATVs. After doing all this it still had problems but it wasnt as bad the faster you went. On pavement you can hardly hold onto the handlebars under 10mph because it shakes so bad. Once you increase speed its still there but controllable. Does anyone have any idea what this could be? Its driving me crazy. I rode it like this for a while and one of the axles ended up breaking at the u-joint. I guess it was due to all the shaking. I'm thinking its something to do with the transmission/differential. Give me y'alls input.

Thanks