I have a 2005 walker ghs. the left side wheel seems to die out at times. Not totally but it can be going along straight and then that side slows down to make it want to turn that way. I can pull back on the other side to slow it down and it goes together again. and a few minutes later that left side like dies for a second and comes back in. what do I need to change? I also have bushhog zero turn. The hydro on the right side does not want to pull up on my gate. What is the problem there?