904657-9 – Short Couple Driveshaft – 1710 (1.938 x 6.094) Series – 12.620″ Flange To Flange

904657-9 Short Couple Driveshaft — 1710 Series, 12.620" Flange to Flange, 6.620" CL to CL

The 904657-9 is a 1710 Series short-couple driveshaft assembly with a flange-to-flange dimension of 12.620" and a centerline-to-centerline U-joint distance of 6.620". The 1710 Series is rated for the highest SAE torque loads before the SPL heavy commercial range, using 1.938" cap diameter U-joints with a 6.094" cross width. This assembly is suited for Class 7–8 heavy truck interaxle (tandem jackshaft) installations and other short-coupled flanged driveshaft applications where the mounting distance falls within the 12.620" flange-to-flange range. The assembly is dynamically balanced at the factory.

The 904657-9 differs from the 904657-12 solely in overall length — the 12.620" F-to-F places the U-joint crosses 6.620" apart at centerline, 0.760" shorter than the -12 variant. This 0.760" dimensional step corresponds to the series increment within the 904657 family, allowing precise matching to the measured interaxle distance in the vehicle. The flanged construction means both ends bolt to companion flanges using the 1710 Series flange yoke bolt pattern — there is no slip mechanism in a short-couple assembly.

Specifications

• Part Number: 904657-9
• Series: 1710 (1.938" cap x 6.094" width)
• Flange to Flange: 12.620"
• CL to CL: 6.620"
• Application: Heavy-duty commercial truck tandem axle, interaxle shaft

Fitment & Installation Notes

Measure the flange-to-flange gap in the vehicle chassis before selecting the 904657-9. With the tandem axles loaded to their operating position, the distance between the companion flange faces on the forward-rear and rear-rear axles must correspond to 12.620" for this assembly to install at correct operating angle. Short-couple driveshafts do not telescope — the fixed length means any deviation from the nominal gap introduces angularity error at both U-joint positions. The 1710 Series U-joint retention and cap diameter (1.938") requires 1710-rated companion flanges; substituting 1610 Series components will result in cap diameter mismatch.

The 1710 Series positions this assembly above the 1610 (1.875" cap) and below the SPL55/SPL70 commercial series in torque capacity. It is the standard choice for tandem-drive trucks in the 80,000 GVW class. When replacing a failed interaxle shaft, measure the old assembly and compare flange-to-flange — not the tube length — against the 12.620" specification. If the old shaft is worn or bent, the flange-to-flange dimension of the 904657-9 should be confirmed against the chassis manufacturer's driveshaft installation data.

The 904657-9 is one in the stepped series of 1710 short-couple assemblies covering the interaxle distance range for Class 7–8 tandem trucks. Companion flange bolt circle, pilot diameter, and bolt torque specification must be sourced from the axle manufacturer's service manual for the specific axle model installed. Explore related Short Couple Driveshaft assemblies including adjacent length variants (904657-8, 904657-12) and 1610 Series configurations for lighter-duty tandem applications.