I have not yet been in touch with the machine shop. They are about 3 hours from me, so taking the car to them while not out of the question is not real easy. I will be in the area where the shop is located next week and plan to go talk with them. Agree a properly balanced rotating assembly should not be a source. I don't have a magnetic drain plug and have not taken the oil filter apart. However, I did remove the oil pan and it was very clean. I did not find any obvious metal or other debris.

The insulators and trans mount are rubber aftermarket items that are less than OEM quality IMO. I think I got them from NAPA. The driver side insulator is now an old rubber insulator that was on the engine when I got the car. It has some numbers on it, but don't think it is an original MOPAR part. I installed it yesterday to see if it would solve the problem. It did not. I am going to install an old right side insulator that has a MOPAR part number on it just to see if anything changes. I don't have an old trans mount to try.

John