Ford 9" 40 spline steel spool (3.250" Bearing)

Mark Williams steel spools are precision machined from US Made 4140 steel forgings on CNC machinery for ultimate precision and accuracy. The ring gear register and bearing diameters are precision ground with the spool mounted on a special arbor to assure concentricity between the splines and the ground surfaces and final ground to ensures zero runout on the ring mounting surface. Engineered for maximum reliability, MW spools have an increased cross-section under the ring gear register to prevent ring gear deflection. MW spools are heat treated in-house with the same austemper through hardening heat treat process as our strongest in class MW “Hi-Torque” axles for ultimate strength. 

The Mark Williams Advantage

• Through hardened alloy steel, not egg-shell-thin hardened case
•  Ring gear mounting diameter is ground to precise press fit
• All mounting diameters concentric and square within .001"
• Increased cross section and generous radius under mounting prevents deforming
• Made in the USA! Forged, Ground, Machined, and Heat Treated in the USA!

Mark Williams 40 spline steel spool for use with 9" Ford Rear End. Requires 3.250" bore case including the 57440 Mark Williams aluminum and 57470 Mark Williams nodular cases, and also requires 45mm wheel bearing (p/n 58505). Profile milling and cross-hole drilling saves 2-1/2 pounds over standard unit. Manufactured from through hardened 4140 high strength steel.

Instructions: SB0046

Features:

• Cut for 40 spline axles 
• 4140 Through hardened steel
• Uses 7/16 bolts
• Weighs 11 pounds
• Made in the USA

Note: We recommend replacing ring gear bolts every time a new gear is setup.