• Much thicker than the stock cover, for increased strength. Stock covers are a well-known weakness of the Cobra IRS. This cover provides increased strength without the need for an additional brace.
• Reduces the possibility of cover breakage or oil leaks.
• Modified by MM to install along with MM aluminum differential mounts that allow adjusting pinion angle.
• May be installed with stock rubber mounts and direct replacement urethane mounts.
• Load bolts provide additional support for the differential bearing main caps.
• Separate ports for draining, filling, and checking the level make servicing much easier.
• Includes provisions for oil cooler inlet and outlet.
• Easily drilled and tapped for a temperature sensor.
• Machined groove on mounting surface captures silicone sealant to form a better seal.

• Direct replacement FRPP design fits like an OE part should.
• Thick, high-strength aluminum casting provides far greater strength than the breakage-prone stock cover.
• Precision-machined recesses for clearance to IRS cradle when installed along with MM aluminum differential mounts.
• Load bolts
• 10 attachment bolts and washers
• Machined groove on sealing surface

Fits

• 1999-2004 Mustang Cobra IRS
• MM aluminum differential mounts that lower the differential cover
• Stock rubber differential mounts
• Direct replacement urethane differential mounts

Why does the stock differential cover break?
The primary cause of cover breakage is the impact loads during wheel hop. The stock rubber bushings allow the center section to flop around violently, which can easily break the thin stock cover. Aluminum differential bushings prevent movement of the center section, greatly reducing the possibility of cover breakage. A stronger cover such as the FRPP cover is an added layer of insurance against cover breakage.

http://www.fordracingparts.com/download/instructionsheets/FordInstShtM-4033-G3.pdf