Manual Transmission Study

1965 Ford Mustang 4-Speed T-10 Transmission


Entire unit. Shift forks in foreground, 1-2 fork on left, and 3-4 fork on right. Main drive gear (a.k.a. "input shaft," driven by the engine crankshaft when clutch is engaged) is on the right. On far left is the case extension, showing linkage that goes ultimately to the stick shift. When mounted on the car, coming out of the case extension would be the driveshaft, with U-joint, connecting to the rear differential to drive the rear wheels.

The photo shows the tranny upside down to the way it is oriented when bolted to the Mustang chassis. That is, when the transmission is installed, the shift forks come out of the driver's side of the transmission case.


Zoom in. Note the reverse shifter lever on the left. Just to the right of it you can see two spur gears. The larger spur gear is the reverse gear. The smaller spur gear is the rear reverse idler gear.


Zoom in again. The lower set of gears is the mainshaft with, from left to right, 1st gear, brass synchronizing ring, 1-2 clutch sleeve (clutch hub underneath), brass synchronizing ring, 2nd gear, 3rd gear, brass synchronizing ring, clutch sleeve (clutch hub underneath), brass synchronizing ring, main drive gear (which doubles as "fourth gear", a.k.a. "direct drive").

The upper set of gears is the countershaft, a.k.a. the countergear or clustergear. Four gears are mounted on the countershaft. The left-most countershaft gear (meshing with 1st gear) is not visible in the photo, because the small, front reverse idler gear hides it. Note that the front reverse idler gear teeth slant in the same direction as the teeth on 1st gear. Therefore, these two gears cannot mesh. It only seems like they mesh because the photo does not capture all the detail. The front reverse idler gear meshes with the left-most gear on the countershaft.