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How manual transmissions work

Gearboxes and manual transmissions

Here at Newcastle Gearbox & Diff, we provide service and repair for virtually every component of manual transmissions and gearboxes. To help you understand a bit more about what we do, we’ve put together this quick and simple guide informing you of what exactly it is that manual transmissions do and the components involved.

Essentially, gearboxes ‘smooth out’ the torque curve of an engine, allowing it to run at the highest speed with the engine running at it’s most efficient range.

The ‘input’ shaft does just that – transmits power through the layshaft, a unit containing the number of gears the gearbox has (3-speed, 4-speed, 5-speed, 6-speed, etc.) From the layshaft, power is transmitted through each specific gear and further carried to the drive shaft, where it propels the vehicle.

On the drive shaft itself is where you’ll find gears, the number of which will be relative to the number of gears found on the input shaft. On manual transmissions, the number of gears is often limited to 6.

Next to each gear sits a synchronizer. When you select a specific gear using your gear lever, the synchronizer is forced against the gear. This locks the gearbox into place and into gear. This allows the vehicle’s engine to operate, as stated earlier, at the highest possible efficiency for a specific speed, based on the gear you’ve selected.

Now, this is quite a basic explanation of what a manual transmission does. But even with this simple phrasing, you can see that a gearbox is an instrument that’s assembled with precision. Inside each unit, you’ll find several rings, nuts, springs and washers that ensure everything is held in place and operates within a controlled range of motion.

Entrust Newcastle Gearbox & Diff to make sure that your gearbox is running as smoothly as possible by performing regular maintenance and repair on these components. We keep a stock of gearbox components, including the following:

  • Bellhousing
  • Extension housing
  • Retainer plates
  • Synchronizers
  • Various lock nuts, washers and springs
  • Spacers
  • Counter gears