Transmission Rumble

[sjbabs]

I'm rebuilding the engine of my ' 64 220SB. In the meantime, a fellow gave me an engine I think is from a '72 250C. I had to change the flywheel, but otherwise it seemed to fit. Now I have this aweful rumble that seems to come from the transmission/torque converter area. I've drained the trans and converter, but still have the rumble. It seems to be RPM dependent, and not MPH dependent. It definately increases until the car shifts, then becomes less pronounced. The sound occurs even when the car is not moving. My young daughter announced that is was good this very expensive car gives a vibration massage every time you ride in it. Any ideas on where I might start to resolve the problem?

[300SDog]

Flywheels are individually ballanced to crankshaft, connecting rods and pistons for each engine as a unit. Neutral ballancing of the flywheel when swapping from one car to another is generally considered a good idea.

But wait - check the tranny mount first. It's got a track mounting with variable positioning. Maybe loosen it a bit and roll the car back'n forth so it can settle in place then tighten it up. Driveshaft orbiting at the flex-disc occurs when the tranny mount is not in position exactly.

[sjbabs]

thanks for the tips. I never touched the tranny mount when changing the engine, but I'm willing to give it a try. Is it your sense that the torque converter is not the likely culprit, and the flywheel might be?

[300SDog]

Sorry didnt consider the torque converter, have little experience there. But I'd sure start with tranny mounts first.