3-28-427U – Weld Yokes – 1350 Series – Butt Dia 3.321″ – Tube Dia Wall 3.500×0.095

Q: What is the 3-28-427U and how does it differ from the 3-28-427?
A: Both are 1350-series weld yokes for 3.500" tube with 1.840" CL-to-weld. The 3-28-427U fits 3.500"x0.095" tube (3.321" butt, same as all 3.500"x0.095" yokes in the catalog) while the 3-28-427 fits 3.500"x0.083" tube (3.344" butt). The 0.023" butt diameter difference tracks the 0.012" wall-per-side difference.

Q: Why is the 1350 CL-to-weld (1.840") shorter than the 1410 (2.125") and 1480 (2.031") at the same tube size?
A: The 1350 U-joint body is smaller than the 1410 and 1480 bodies -- the smaller joint occupies less space within the yoke, allowing the weld shoulder to sit closer to the joint centerline. This is the expected engineering relationship: smaller series = shorter CL-to-weld at the same tube size. Mixing the CL-to-weld between series when calculating shaft length will produce errors of 0.185"--0.850" in assembled length.

Q: Is the Spicer-brand "U" suffix significant?
A: In Spicer nomenclature, the "U" typically indicates a specific OEM specification variant -- the yoke meets Spicer's OEM-grade tolerance standards for dimensional precision, surface finish, and material hardness. This makes the 3-28-427U appropriate for OEM-quality truck driveshaft repair requiring Spicer-equivalent precision.