I recently purchased a 2011 Yukon with 95000 miles on it it is 2 wheel drive. When I purchased it I noticed a ticking sound coming from the exhaust and determined the location of the leak. Where the header ends there is a 3 bolt flange going to the next pipe section it is leaking at that flange and I can tell that somebody recently installed a new bolt. Is there a donut or a gasket or anything in there that I need before tackling the job. I haven't check the motor mount yet this is on the driver side what is the chance the motor mount is causing the exhaust leak. I'm new here to this particular forum thanks for your help I look forward to your answer