The synchromesh transmission also has gears in
constant mesh. However, gears can be selected without
clashing or grinding by synchronizing the speeds of the
mating part before they engage.
The sliding gear transmission is generally used in
farm and industrial machines; therefore, we will only
look closely at the constant mesh and synchromesh
Constant Mesh Transmission
To eliminate the noise developed by the spur-tooth
gears used in the sliding gear transmission, automotive
manufacturers developed the constant mesh trans-
mission, also known as the collar shift transmission
(fig. 4-18). The constant mesh transmission has
parallel shafts with gears in constant mesh. In neutral,
Figure 4-18.Constant mesh transmission assembly.