Label Parts of the Manual Transmission

A four-speed gearbox cut open from the side: nine numbers, a line for each name, and a key.

Label Parts of the Manual Transmission

Name Date

Numbered worksheet

1 2 3 4 5 6 7 8 9
More options

Write the name of each numbered part.Answer key

  1. Input shaft
  2. Main shaft (output shaft)
  3. Countershaft
  4. Synchronizers
  5. Shift forks
  6. Shift rails
  7. Gearshift lever
  8. Reverse idler gear
  9. Transmission case

Drawn for this site by script, 2026-09-27. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step The labeled gearbox, and how it changes gear

All 9 parts on the diagram

Show the list
  1. Input shaft The shaft driven by the engine through the clutch. Its gear turns the countershaft.
  2. Main shaft (output shaft) The output shaft, on the same line as the input shaft. Its gears turn freely until a synchronizer locks one of them to it.
  3. Countershaft The shaft below, turned by the input shaft's gear. Its gears are always in mesh with the main shaft's gears.
  4. Synchronizers Main-shaft collars that match a gear's speed to the shaft's. They then lock the gear to it, so the gears change without grinding.
  5. Shift forks They slide a synchronizer's collar along the main shaft. They are fixed to the shift rails.
  6. Shift rails Rods moved by the gearshift lever, each carrying a shift fork.
  7. Gearshift lever The lever the driver moves to choose a gear. It pushes one shift rail at a time.
  8. Reverse idler gear An extra gear that makes the main shaft turn backwards. It sits between the countershaft and the main shaft's reverse gear.
  9. Transmission case Holds the shafts in their bearings. Also holds the oil the gears run in.

How this list was compiled: Read 2026-09-27. (1) US Army, TM 9-8000, Principles of Automotive Vehicles (1985), chapter 22 (paragraphs 22-1 to 22-8 and figures), https://archive.org/details/tm-9-8000-principles-of-automotive-vehicles-1985 : the input shaft, main shaft and countershaft of a constant-mesh transmission; the reverse idler gear; synchronizers; shift forks on shift rails (shifter shafts); the gearshift lever; the transmission case. (2) Wikipedia, Manual transmission, https://en.wikipedia.org/wiki/Manual_transmission : constant-mesh transmissions with an input shaft, a countershaft (layshaft) and an output shaft; output-shaft gears that turn freely on bearings until locked by a collar; synchronizer rings; the selector fork linked to the gear lever and the selector rods; an idler gear for reverse; the transmission casing. Licence: own work

The drawing: Drawn for this site by script, 2026-09-27. Own work, nothing traced. Licence: own work

How it works

Label parts of the manual transmission illustrated above by writing each name on its numbered line. The engine end is at the left.

Read the full guide

Manual transmission word bank

In alphabetical order, to copy onto the board: countershaft, gearshift lever, input shaft, main shaft (output shaft), reverse idler gear, shift forks, shift rails, synchronizers, transmission case.

Numbers that get swapped

Three shafts: 1 comes in at the left (input shaft), 2 leaves at the right on the same line (main shaft) and 3 lies along the bottom (countershaft). 6 is the long bar across the top (shift rails), 5 one of the dark bars hanging from it (shift forks) and 4 the collar a dark bar holds (synchronizers). 8 is the small gear at the right end (reverse idler gear), not one of the tall blocks.

  • When marking, layshaft is right on line 3, output shaft on line 2 and selector forks on line 5.
  • The tall blocks between the shafts are the gears, seen edge-on. None of them has a number.

Questions and answers

What is a constant-mesh transmission?

A gearbox whose gear teeth stay in contact all the time. The gears on the output shaft spin freely until a collar locks one of them to the shaft. Most modern manual transmissions are built this way.

How many gears does a manual transmission have?

A car today typically has five or six forward gears and one reverse. Gearboxes with as few as two and as many as seven have been made. The one on this worksheet is a four-speed.

Why does reverse gear whine?

The reverse gears usually have straight-cut teeth, which whine as the car backs up. The forward gears have helical teeth, which do not.

Is a stick shift the same as a manual transmission?

Yes. Stick shift is a name used in the United States and Canada. Standard transmission and manual gearbox are two more names for the same thing.

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