In the days before GotTransmissons.com was even a thought, changing or shifting from gear to gear was a delicate and potentially damaging operation requiring considerable skill. Straight-cut gears had to be matched in speed, synchronized, Â before being brought into mesh together. The result was an unfriendly grinding noise – clashing of the gears, as it was known.
FYI: These old types of transmissions used conventional heavy weight gear lube during a maintenance. Synthetics were not even developed as far back as then. However, if you had an old autombile or truck with the straight cut gears, synthetic lubrication is an upgrade.
To change gears on a straight cut or ‘rock crusher’ gearbox you must disengage the clutch, shift to neutral and let the engine run down to a lower speed, re-engage the clutch briefly in neutral to slow the gears down, then select the new, higher gear. To change down you need even more pedal dexterity: you disengage the clutch, shift to neutral, re-engage the clutch, tap the throttle rapidly to spin the gears up, depress the clutch again and select the new, lower gear.
This process, known as double clutching, is almost a lost art form. Many mature owners are familiar with the technique. But for the rest of us, the juggling with clutch, throttle and gearstick (while braking with your third foot!) is alien and unfamiliar.
The reason we no longer need to go through the double clutch procedure is the invention of the synchromesh gearbox AKA The Constant-Mesh Gearbox. Straight-cut gear boxes are very noisy, it wasn’t long before engineers began to experiment with other methods, most notably helical gears in constant mesh. It is well worth understanding how this process works – it will make you a better driver by understanding the pardigm behind the gear style change.
See our next post presented by GotTransmissions.com Blog for a continuation in your standard transmsiison eduaction. Next, what is a Helical Gear is and how it functions?
