Trans Dapt Red Polyurethane Transmission Mount for Ford C4, C6, FMX Automatic and 3 or 4-Speed Manual Transmissions. If you have excessive driveline movement due to the flexible nature of stock rubber mounts, polyurethane has a higher durometer (firmer) to prevent excessive movement without being unduly harsh. Polyurethane also is more durable and will not deteriorate like stock rubber pads. This mount, sometimes referred to as an insulator or pad, bolts in as a direct replacement for that old rubber mount.