inspection of my Grand L I noticed cracks around the bolts on the Rear Drivers side. Numerous times a year I check these bolts and torque them. It seems the drivers side keep loosening because of rotation I suppose. The tractor is light duty with a FEL/ BH and used on dirt and gravel. I have 350 hours with the tractor being 6 years old. Would anyone think this may be a manufacturer defect? Please see photos