I just bought a 2006 Z Force 44 I am new to the whole zero turn riders. It was in storage 2 years and has had about 20 hours put on this summer for a total of 90 hours. When the control levers are pushed forward the right is smooth but the left has a "grinding" noise. It also "lurches" while moving in a straight line and jumps to left as if it "missed". Any troubleshooting that can be done? The trans is sealed except for the vent pipe on top.???