Most remote control rods are cranked at the gear lever end. Incorporating plain bearings or bushes would not affect the back and forth movement of a simple rod but they would clearly prohibit side to side action. Also, the distance between the lever and the striker arm is often around 70 cm (2ft) and a rod of this length must be supported in bearings if it is to transmit the gear lever's movements smoothly and without any flexing. A rod that is simply bolted to the gear lever and striker arm could move in both directions, but its action would undoubtedly be harsh. The connecting rod must obviously be able to duplicate these movements. Most stem from the fact that a gear lever must move in two planes, forward and back and then from side to side to move across the gear "gate". This may sound simple enough but there are problems involved in this type of linkage. Most floor-mounted, remote control mechanisms are based on a rod, though cables have been used, the rod running forward from the gear lever to the striker arm in the gearbox.
![gear shift gear shift](https://www.winwinzone.co.uk/winwin/1600/aa572/aa572_g3.jpg)
The answer was to incorporate a remote control mechanism between the lever and the gearbox. If it was it would have been extremely awkward for the driver, being either too far forward or so long that efficient, accurate changes would be difficult to achieve.
![gear shift gear shift](http://freebie.photography/transport/slides/gear_shift.jpg)
It did mean, though, that the gearbox was mounted further forward than it used to be and this, in turn, meant that a floor-mounted lever could not be directly coupled to the gearbox. This gave greater rigidity to the transmission, as well as cutting manufacturing costs. The modern practice is to bolt these two major components together, in what became known as "unit construction". In early cars the lever ran straight down into the gearbox because the engine and gearbox were separated by a short shaft and this brought the gearbox into a convenient position for a directly-acting lever. The gear changing mechanism starts, quite obviously, with the gear lever.
![gear shift gear shift](https://ae01.alicdn.com/kf/HTB157zjc6fguuRjSspkq6xchpXaB/Gear-shifter-LED-sensor-light-illuminator-head-touch-light-car-styling-accessories-Gear-Shift-Knob-Auto.jpg)
There are three distinct parts to a gear change mechanism: the lever itself and its connections to the gearbox, the sliding forks that move the dog clutches in and out of mesh ( and, in between, the fork selection mechanism. A typical four-speed gearbox will, for example, have three dog clutches, one for third and fourth gears, another for first and second and the third to engage reverse. The advantage of this is that fewer dog clutches are needed. Most dog clutches are in fact double-ended designs, which means that if they are moved in one direction they will engage one gear, if they are moved far enough in the other direction they will disengage from the first pinion and then engage a second. To engage a gear the dog clutch must be slid up the mainshaft, to disengage it the dog clutch must be moved back down the shaft. The heart of the gear changing action is in the sliding of the dog clutches. This gear is locked to the mainshaft through the dog clutch's splines. The centre of the dog clutch is splined to the mainshaft and teeth at one end mesh with a matching set on the gear to be engaged. Locking the gears to the mainshaft is effected by synchromesh-equipped dog clutch assemblies. This action will then provide a solid link between the layshaft and the mainshaft. Therefore, to bring a pair of gears into action, the mainshaft gear has to be locked to the shaft.
#Gear shift free#
This means that the gears on the layshaft are an integral part of it, while those on the mainshaft are free to revolve without turning the shaft. The pinions on the modern gearbox are in constant-mesh.
![gear shift gear shift](https://www.dsf.my/wp-content/uploads/2016/08/gear-knob_pdk.jpg)
Gear changes are no longer made by sliding the actual pinions in and out of mesh.
#Gear shift driver#
Modern driving conditions demand that the driver makes frequent gear changes and a mechanism that is temperamental or inaccurate can be both frustrating and dangerous as well as physically tiring. It must be quick and smooth in action, efficient and totally reliable. The gear change mechanism is a component that is too often taken for granted but it is one of the more important features of the car.