SOUTH BEND ISK1.25 INPUT SHAFT – 1-1/4" 10-SPLINE – 1994–2004 DODGE RAM 5.9L CUMMINS (NV4500)

Restore the strength and reliability of your NV4500 with the South Bend ISK1.25 factory-diameter input shaft. This 1-1/4" (1.25") 10-spline shaft is a direct-fit replacement for 1994–2004 Dodge Ram 2500/3500 trucks equipped with the 5.9L Cummins and the NV4500 manual transmission.

• Size: 1-1/4" (1.25") 10-spline
• Application: NV4500 manual transmission behind 5.9L Cummins
• Use: Direct replacement for worn/damaged factory input shafts
• Note: Does not fit NV5600

FITMENT

• Engine: 5.9L Cummins
• Model Years: 1994–2004 Ram 2500/3500 (NV4500 only)
• Transmission: New Venture NV4500 5-speed

WHAT'S INCLUDED

• (1) South Bend ISK1.25 1-1/4" 10-spline input shaft

Tip: Inspect pilot bearing, release bearing, and clutch assembly during installation; replace if worn.

CROSS-REFERENCE / ALTERNATIVES

• CPP Extreme Duty NV4500 1.375" Input Shaft (upgrade path)
• South Bend HYD-HD Hydraulics (1994–1997)
• South Bend HYDX1.50 Hydraulics (1998–2002)
• South Bend HYDX.750 Hydraulics (2003+)

HELPFUL NOTES

• Verify transmission model before ordering. This ISK1.25 fits NV4500 only.
• Upgrading to heavy dual/triple-disc clutches? Consider moving to a 1.375" input shaft for added strength.

FAQ

No. ISK1.25 is for the NV4500 only. NV5600 applications (especially HO) typically use a 1-3/8" input and different parts.

Factory-size replacement at 1-1/4" 10-spline. For higher power or heavy towing with multi-disc clutches, see the 1.375" upgrade.

Inspect the pilot bearing, release bearing, and clutch hydraulics. Replacing worn components prevents premature wear and engagement issues.