The Eaton Fuller countershaft square key, part number 4304840, is a transmission driveline component used to locate and lock gears or related parts on the countershaft of an Eaton Fuller transmission. The square key seats in a matching keyway to transmit rotational load and keep mating parts indexed during operation. Because keys are application-specific to the transmission model and countershaft configuration, verify this part number against your unit before ordering. Not sure this is your part? Give us a call to confirm the correct fit for your transmission.
Interchanges:
- Fuller 19673
- Fuller 16638
- Fuller 20194
- GMC 2099882
- Mack 3088-16638
- Mack 3088-20194
- Mack 308819673
- Navistar 407757C1
- Navistar 591891C1
- Mack 3088-4304840
Found in these kits and assemblies:
| Kit Number | Kit |
| K-1926 | Kit Countershaft |
| S-3039 | Countershaft Right Assembly |
| S-3040 | Countershaft Left Assembly |
Features
Eaton Fuller part number 4304840
Countershaft square key for Eaton Fuller transmissions
Locates and locks gears or components on the countershaft
Square key profile seats in a matching keyway
Sold by Pro Gear and Transmission
Used in 307 Eaton Fuller models
