Strange-STG D1554 Spool Full Size Steel 33-Spline 10-Bolt 9 in. Each For Ford. Part Number: D1554. Axle Shaft Spline Quantity: 33. Notes: Fits 2.891 and 3.0625 bore cases. Spool Material: Steel. They’re CNC-machined from forged chromoly steel to provide a more rigid ring gear mounting.