A tie bar assembly includes front and rear units each including inner inserts interconnected with outer inserts with webs of elastomeric material. A pole sub-assembly is disposed between the units. The pole sub-assembly and the units define front and rear fluid chambers containing a magneto-rheological fluid. Fluid orifices are disposed through the pole sub-assembly for flow of the magneto-rheological fluid between fluid chambers. An electromagnet coil generates an electromagnetic field to affect viscosity of the magneto-rheological fluid. A connecting rod connects inner inserts and is slidably disposed through the pole sub-assembly for causing movement of the magneto-rheological fluid between fluid chambers. A displacement sensor detects movement to generate a signal to the electromagnet coil. Front and rear travel cushions are each disposed on the inner inserts for limiting the movement of the inner inserts toward the pole sub-assembly.