Assembly Matrix
Manual Transmission Gears Parts 2025
Overview of assemblies, gear compatibility, spline types, and roller configurations.
‘Syracuse’ M23: The Champion, Reimagined
The Muncie M23 is the strongest, fastest-shifting synchronized 4-speed on the market — purpose-built for musclecars, hot rods, and custom performance applications.
Whether you’re building a street legend or a track machine, the M23 delivers unmatched durability and shift feel — all in the classic Muncie footprint.
Why Choose the M23?
- ✅ Smooth shifting, optimized RPM drop
- ✅ Supercase standard with SAE 9310-equivalent countershaft
- ✅ Stronger gear geometry + polished contact surfaces
- ✅ SCCA-approved options available
- ✅ AutoGear “controlled-clearance” synchronizers for fast, durable shifts
Gear Ratio Packages
| Model | 1st Gear | 2nd Gear | 3rd Gear | 4th Gear | Best For |
|---|---|---|---|---|---|
| M23X | 2.199 | 1.506 | 1.174 | 1.00 | Road course & high-rev builds |
| M23W | 2.599 | 1.908 | 1.483 | 1.00 | Street/track blend |
| M23Z | 2.984 | 2.225 | 1.468 | 1.00 | Drag & street torque builds |
Additional ratio codes available (314, 324, 334, etc.) — Contact us to find your match or look at our full Ratio Chart here.
What You Get
- ‘Muncie’ install footprint — reuse clutch, shifter, driveshaft
- Masiero Italian gears — rarely equaled, never bested
- N-Series Supercase + mainshaft = rugged and vibration-resistant
- Controlled-clearance synchros + Kyowa rings = built for fast shifts under pressure
- Oil-sealed, torsion-cushioned 26-spline inputs for torque shock protection
- Cast and machined in the USA with aircraft-grade aluminum
Resources
View documents and resources related to this gearbox in the resource center.
View ResourcesThe Complete Guide
AutoGear Gearbox & Gearset Option Codes
Overview of assemblies, gear compatibility, spline types, and roller configurations.
Assembly Matrix
Manual Transmission Gears Parts 2025
Overview of assemblies, gear compatibility, spline types, and roller configurations.
The Complete Guide
AutoGear Gearbox & Gearset Option Codes
Overview of assemblies, gear compatibility, spline types, and roller configurations.
Not Sure Which Ratio Is Right?
Submit an EZ-Spec and our team will reply with a personalized recommendation.
Our mission? To be the best today — and better tomorrow.