Just got my 2003 Polaris Trailblazer 250 back from the shop after a top end rebuild. Now it has a bang and slip in the transmission during fast exceleration or hill climbing. If slow to accelerate it is fine. Shop said it is a worn stretched belt and it couldn't have been from anything they did well working on it. Sounds right, but it wasn't doing this before I took it in and I am new to atvs and not the original owner. Don't want to continue to throw money at this and am willing to try replacing the belt myself, but not sure the belt is the true issue here. Any advice is welcome.