Manual Transmission Quiz: Synchronizer Hub Functions

Study Notes

Most vehicles with manual transmissions use a floor-mounted shifter.
Shift forks control shifts between gears and interlocks prevent accidental selection of reverse or two gears at the same time.
Synchronizers make shifting easier by synchronizing the speeds of the gears to be meshed.
Synchronizer assemblies include a hub, sliding sleeve, blocker ring, keys, and springs.
The synchronizer goes through three stages during a shift: misalignment, relaxation, and alignment.
Synchronizer stop rings are a type of cone clutch and are made of softer metal to absorb friction.
The internal splines and coupling gear teeth have a special shape to hold the gear engaged once the driver releases the shift lever.
Back taper is an angle cut opposite to the chamfer that creates resistance to motion to keep the splines from sliding off the coupling teeth.
Keys and detent key springs limit the amount of rotation of the ring and keep the sliding sleeve in the neutral position.
Some synchronizer stop rings have friction material on the cone surface and require automatic transmission fluid.
A five-speed transmission has six gear sets for five forward speeds and one reverse speed.
The Borg-Warner T5 manual transmission is a contemporary five-speed design.
The T5 provides three gear reduction ratios, direct drive, and an overdriven ratio.
Sliding idler gears are used to change output shaft direction and provide reverse.
Neutral is when all synchronizer sleeves are centered on their hubs.
First gear ratio is achieved by locking the first speed gear to the output shaft.
Second gear ratio is achieved by locking the second speed gear to the output shaft.
Third gear ratio is achieved by locking the third speed gear to the output shaft.
Fourth gear is direct drive at a 1:1 ratio with no gear reduction.
Reverse gear can be achieved with either sliding or constant-mesh gears.