Overview
The G2 Ford 9.75 Inch Ball Milled Aluminum Cover (part 40-2012MB) is a cast aluminum rear differential cover for Ford 9.75 inch axles.
G2 cast this cover to help move heat out of the gear oil, which the company says supports longer bearing life. Ball milled ribs stiffen the cover, and the body is heat treated and shot peened to take direct blows. Its extra oil capacity gives the gear oil more volume to work with.
Service plugs like these let the gear oil be checked and drained without a full teardown, which matters on a rear axle that gets regular oil checks. The ball milled ribs add rigidity while keeping the cast body reasonably light.
Key features
- Lightweight cast aluminum body
- Ball milled ribs for added rigidity
- Heat treated and shot peened body for direct impact
- Fully machined seal surface
- Filler, fill level and drain plugs
- Dipstick for maintenance
- Powder coated finish
Fluid and cover care
The differential cover is the access point for checking gear oil, so its plugs and seal see regular use. Wipe the surface clean before opening a plug to keep dirt out of the gear case. A cover that is cracked or bent at the bolt flange should be replaced, since even a small gap lets oil seep out over time.
Aluminum covers expand and contract more than steel as temperatures change, so retorque the cover bolts after the first heat cycles and check for weeping oil. When changing gear oil, use the oil type suited to the axle and carefully inspect the drain plug for metal debris. Keep the dipstick and fill plug threads clean so they seal properly at each service.
Specifications
| Brand | G2 Axle and Gear |
|---|---|
| Part number | 40-2012MB |
| UPC | 631410113068 |
| Material | Aluminum |
| Finish | Powder coated |
| Axle location | Rear |
| Axle type | Ford 9.75 inch |
| Oil capacity | Extra |
| Service plugs | Filler, fill level and drain |
| Dipstick | Included |
Vehicle fitment
Fitment follows the axle size, so the cover is for Ford 9.75 inch rear axles. Match the axle size to your housing before ordering.
Measure your axle housing to confirm it is a 9.75 inch unit before buying a cover for it.
What’s included
An aluminum cover with filler, fill level and drain plugs and a dipstick.
Not included: Gear oil.
