These polyurethane inserts fit into and fill the voids in the factory differential bushings. By filling these are gaps, the movement of the bushing is limited for better stability under acceleration and smoother shifts. Avoids the hassle of a full bushing replacement with these inserts - no need to press/burn out the old bushings, the inserts just slide right in to the factory bushing.
Fits bushings in OE bracket with part number NA5F 39730 and fits manual versions only.
Requires removal of the differential to install.
The race version of these bushings are a stiffer durometer for track ONLY cars.