More info: My car is an '84 Euro 300D NA automatic (722.405) and the donor motor came out of a 1983 Euro 300D NA with a manual transmission. My mechanic transferred the flywheel from old to new motor but had to use the flywheel bolts from the automatic old motor as the manual tranny bolts were different. Does this sound right? Could I have a flywheel balance issue?

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1984 Mercedes Euro 300D NA
1997 Ford F-350 Powerstroke Turbo Diesel