Sonnax 100420-01K Transfer Case Split Ring Retainer NP230 NP240 1.180in Shaft

The Sonnax 100420-01K Transfer Case Split Ring Retainer is a direct upgrade replacement for the OE open-end style snap ring used in New Process 230 and 240 Series transfer cases with a 1.180" diameter, 27-spline output shaft. This kit is engineered to permanently solve one of the most common transfer case failures: a broken retaining ring behind the rear output shaft bearing.

The factory OE snap ring is an open-end design that sits directly behind the rear output shaft bearing. During normal operation, spline lock causes the driveshaft to load the snap ring with forward force rather than sliding freely on the output shaft spline. As the rear suspension cycles up and down, this repeated hammering causes fatigue cracks to develop, ultimately leading to snap ring failure.

Key Features:

• Upgrade over the OE open-end style retainer that commonly breaks
• Constructed from high-strength chromoly steel, through-hardened for superior strength and wear resistance
• Unique split ring design eliminates the weak point of open-end snap rings
• Drop-in fitment — no modification required to the shaft or mating components
• Fits New Process 230 Series transfer cases with 1.180" (2.997 cm) diameter, 27-spline output shaft

What's Included:

• Split Retainer
• Retainer Ring
• Snap Ring

The Sonnax 100420-01K is a Made in USA solution for shops and DIY builders looking to prevent or repair rear output bearing snap ring failures in NP230 and NP240 transfer cases. Cross-reference part numbers include S100420-01K and SM308895AK.