The Eaton Fuller 21501 is the countershaft 2nd gear used in RTX and RTXF 609-series heavy-duty transmissions. Per the Eaton illustrated parts list, this gear is item 7 in the Countershaft Assembly group for the RTX-12609P and related models, with a listed quantity of 2 per assembly. Part number 21501 was superseded by 21542 in the RTX-12609P manual. It also cross-references with 22775, which is the updated countershaft 2nd gear in later RTX-11609P and RTX-13609P manuals; those entries note that 22775 must be used with 22774. Confirmed fitment spans 16 transmission models including RTX-11609P/R, RTX-12609P/R, RTX-13609P/R, RTX-14609P/R, RTXF-11609P/R, RTXF-12609P/R, RTXF-13609P/R, and RTXF-14609P/R. Call us to confirm proper fit for your specific serial number.
Features
Countershaft 2nd gear for Eaton Fuller RTX and RTXF 609-series transmissions
Installed quantity: 2 per countershaft assembly
Superseded by Eaton Fuller 21542 in RTX-12609P applications
Cross-references with updated gear 22775 (note: 22775 requires companion gear 22774)
Fitment covers 16 transmission models: RTX/RTXF 11609 through 14609, both P and R suffix variants
Genuine Eaton Fuller part sold by Pro Gear and Transmission
Tech Specs
- Eaton Fuller Part Number: 21501
- Superseded By: 21542 (RTX-12609P)
- Cross-Reference: 22775 (RTX-11609P, RTX-13609P)
- Assembly Group: Countershaft Assembly
- Quantity Per Assembly: 2
- Application: RTX-11609P, RTX-11609R, RTX-12609P, RTX-12609R, RTX-13609P, RTX-13609R, RTX-14609P, RTX-14609R, RTXF-11609P, RTXF-11609R, RTXF-12609P, RTXF-12609R, RTXF-13609P, RTXF-13609R, RTXF-14609P, RTXF-14609R
Used in these Eaton Fuller models
