For the past 2 weeks my car's been making this odd hum/grinding noise, something that i thought might've been transmission wine or something. So, i checked my mtx fuild and filled it up to the filler plug, took about 1/4 a quart (i think its leaking slightly). The sound was still there even after driving 40+ miles. Then i get off the highway yesterday, 75mph for 80 miles, and the sound is really noticable now. I'm thinking its a leak and my exhaust cause it changes with engine speed and i'm hoping its a gasket, because my pipes are not that old, and are hardly rusting. Has anyone had expirence with changing the gasket between the downpipe and the mid-pipe, right near the shift linkage? And it is possible to do on your own? Thanks for any ideas