[billheis]

Well first off your balancer is what is causing your shudder. Don't run the engine again until you put a new balancer on. You need to pull off the old one and check to see if it has damaged the front cover at all. I had one break before and it took out the timing chain. If it looks real bad you might go ahead and take off the front timing cover and inspect timing chain, and drain the oil and look for metal. Once you have that problem taken care of, you might be able to restart engine, keeping a close watch of oil pressure and listen for any noises. As far as the gear oil on the muffler that is probably the pinion seal leaking. I'd start with the balancer first. If you are running it hard you may want to invest in a good balancer.