904657-12 – Short Couple Driveshaft – 1710 (1.938 x 6.094) Series – 13.380″ Flange To Flange

904657-12 Short Couple Driveshaft — 1710 Series, 13.380" Flange to Flange, 7.380" CL to CL

The 904657-12 is a 1710 Series short-couple driveshaft assembly built for heavy-duty commercial truck tandem axle and interaxle applications. The 1710 Series uses a 1.938" cap diameter U-joint with a 6.094" overall cross width — the highest-torque SAE series before the SPL range — and is the standard for Class 7–8 trucks, severe-duty vocational vehicles, and tandem-drive configurations. The 904657-12 has a flange-to-flange dimension of 13.380" and a centerline-to-centerline (CL to CL) U-joint distance of 7.380". Factory balanced prior to shipment.

Short-couple driveshafts are used as interaxle (jackshaft) connections between the forward rear axle and the rear rear axle in tandem-drive configurations, and as short intermediate shafts between transmission and transfer case in certain heavy truck layouts. The 904657-12 is a flanged assembly — both ends use flange yokes that bolt to companion flanges on the axle or gearbox. The difference between flange-to-flange (13.380") and CL-to-CL (7.380") reflects the physical length of the flange yoke bodies at each end. The 6.000" difference accounts for the two yoke body lengths combined.

Specifications

• Part Number: 904657-12
• Series: 1710 (1.938" cap x 6.094" width)
• Flange to Flange: 13.380"
• CL to CL: 7.380"
• Application: Heavy-duty commercial truck, tandem axle interaxle shaft

Fitment & Installation Notes

Before ordering the 904657-12, measure the flange-to-flange distance in the vehicle with the chassis at ride height and the axles at their operating position. Short-couple assemblies have no slip yoke — they are fixed-length. A 0.100" error in installed length produces operating angle error at both U-joints, causing vibration and accelerated wear. Verify the companion flange bolt circle, bolt count, and pilot diameter on both the forward rear axle and the rear input of the rear rear axle match the 1710 Series flange yoke dimensions of this assembly.

The 1710 Series U-joint cap (1.938" diameter, 6.094" span) requires 1710-rated yokes — do not attempt to install a 1610 Series U-joint (1.875" cap) into 1710 yoke bores. The bores are machined larger for 1710 caps and a 1610 cap will have excessive radial play, causing immediate failure. The 904657-12 is used in Class 7–8 tandem-axle trucks, vocational dump, mixer, and refuse vehicles where the interaxle distance places the CL-to-CL within the 7.380" range. Companion flanges must be clean, undamaged, and torqued to the vehicle manufacturer's specification.

The 904657-12 is factory balanced for smooth operation at commercial vehicle operating speeds. When replacing a short-couple interaxle shaft, compare the old shaft's flange-to-flange measurement — not CL-to-CL — against the 13.380" dimension of the 904657-12 to confirm direct fitment. Explore related Short Couple Driveshaft assemblies including other 1710 Series length variants and 1610 Series configurations for different interaxle distances.