Spline Stub 1.750×16 Spline, 3.500 X .095 Tube – 4-40-721 – UDS

Universal Driveshafts 4-40-721U -- Engineered for Series Performance

The 4-40-721U is a series stub & midship shaft engineered to OEM-equivalent tolerances for reliable drivetrain performance. It is engineered to the same geometry as original equipment, so the installation follows OEM procedures without special tooling or adaptation. Universal Driveshafts maintains this part in active inventory because it covers applications that older OEM part numbers no longer reach.

Complete Technical Data

Material and Durability

The 4-40-721U is produced from steel, which provides the combination of yield strength and toughness required for series rated loads. High-strength components in the drivetrain operate at stress levels that are proportional to engine torque -- on a vehicle capable of generating significant torque (diesel trucks, performance builds, heavy towing applications), this means the yoke material is genuinely load-critical. UDS selects materials appropriate for those service conditions.

Ordering and Installation Notes

• Confirm series before ordering -- this is the primary fitment dimension
• Cross-reference any existing part numbers stamped on the component being replaced
• Inspect output shaft or companion flange for damage before fitting the new stub & midship shaft
• Use anti-seize on threads in corrosive environments (undercarriage, marine, off-road)
• Re-torque after initial break-in if this is a first-fit assembly

The 4-40-721U is a stocked catalog item at Universal Driveshafts. Ships promptly with standard packaging for safe transit of precision machined surfaces.