2000 E-320 Question

[JetTech]

I started a thread a few days ago concerning the purchase of either a 98 or a 00 E320. The 98 was sold so we test drove the 00 today. I have one concern with it that I'm hoping someone here can answer.

The car was cold and slanted nose down on the lot. I started it, waited a minute or so, then put it into reverse. In reverse the car started to shudder quite a bit, it was REALLY noticeable which immediately threw up a red flag to me. The trans. wasn't slipping, it was just causing the whole car to shudder while in reverse at idle and off idle when we were backing up. We left the lot and it drove perfectly, shifted perfectly up and down, no problems whatsoever. Back at the lot, after it was warmed up, this shudder was still there but only barely noticeable. Does anyone know if this might be caused by a bad motor mount or anything else?

Thanks in advance,

Dale