MM News

MM supports NASA road racers! MM offers contingency prizes for American Iron, American Iron Extreme, Spec Iron, and the Camaro-Mustang Challenge at both 2017 NASA Championship events, Western and Eastern. Read the details and register now.

Canadians! Please read the latest about ordering from Canada/shipping to Canada.

Turnology drives their S550 after they installed the latest MM Starter Box. Read about the Starter Box and their test drive report.

/DRIVE just released a new video of MM's Mustang in their Tuner car Shootout. We've just posted the parts list and link to the video.

New! MM now offers an adjustable front swaybar for SN95 Mustangs. Currently in stock and ready to ship.

New! MM Starter Box for S550 Mustangs. Includes Koni dampers, MM Caster Camber Plates, choice of Eibach or H&R springs, and Eibach swaybars.

IRS rear differential mount, urethane, with tool, 1999-04 Cobra
Actual product may differ from photo.


  • Item # MMIRSB-46
  • Manufacturer: Maximum Motorsports
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Urethane IRS Differential Rear Mount Kit with tool, 1999-04 Cobra

Reduce wheel hop by installing stiffer differential mounting bushings. MM offers two types of differential bushings, urethane and aluminum. The urethane bushings are much stiffer than the original rubber, yet are still compliant enough to dampen NVH (Noise, Vibration and Harshness). The aluminum bushings allow no deflection at all, and therefore do more to reduce wheel hop. The aluminum bushings are designed to provide adjustment of the pinion angle. Properly setting the pinion angle helps keep driveline vibrations to a minimum.

Unlike many others who offer only the front differential bushings, Maximum Motorsports took the time and effort to actually analyze the IRS system. The MM Engineering Team realized that all of the differential bushings must be replaced as a set. The complete set includes the two front bushings and the essential single rear bushing. If only the front bushings are replaced, and the original rubber rear bushing is left in place, a mismatch will be created in the stiffness of the bushing materials. The more rigid front bushings will deflect less, while the remaining rubber rear bushing will still deflect as much as ever. This in turn will increase the stress on the aluminum front mounting ears of the differential housing. The increased stress can lead to fatigue and stress cracking of the aluminum differential housing. Wheel hop will still be prevalent because the rubber rear bushing will deflect and allow the differential to flop around.

If you had previously purchased a front differential bushing (from somebody other than us!), we offer the rear bushing kit with our removal tool to remove the stock rubber bushing from the factory mount. This kit is designed to prevent potential problems or damage to the differential associated with only having stiffer bushings at one end of the differential.