Looking for a little help out there. I have a Genie 636 GTH. I have a problem with the rear steer. With the controller engaged for front-wheel drive and after a few minutes of driving doesn't seem to matter if it is operating temperature or just on Startup the rear starts to follow the front. I bring it to a stop adjust the controller straighten out the rear tires then start driving again and then shortly it'll do it again. I have rebuilt cylinders in the front and back and I have no other problems it's very smooth not jerky. And from what I read if it is a bypass valve they tend to get jerky or ( like a power steering pump going bad) if that is correct. I read that the controllers are prone to this problem. One of my questions is if it sounds too like a controller am I able to take it apart and clean it or spend a three grand on a new one? Attached a picture of a controller I found on eBay not that I buy a used one if they're notorious for this problem. Thank you