the introduction on the
"In central tube there is a vibration damper, which by way of its elastic mount counteracts the twisting oscillation of the entire transaxle system. Bending oscillation is caused by unbalanced rotating parts of the drive train.
Although the crankshaft, flywheel, clutch and starter gear ring as well as the torque converter are balanced in the plant prior to assembly, residual unbalance can produce vibration, which will be noticed on cars with manual transmission at approx 4200rpm and with automatic transmission at 3300 rpm.
The cast iron vibration damper with rubber spring elements designed for the bending resonance makes the transaxle system insensitive to residual unbalance and permits the replacement of separate components, e.g. during repair, without "assembly balancing" (balancing of flywheel + clutch + starter gear ring together).
For cars with manual the transmission the vibration damper is located in the central tube between the 2nd and 3rd guide bearings.
For cars with automatic transmission the vibration damper is located in the central tube behind the 2nd guide bearing."