Manual transmissions are used in a wide range of automotive applications such as commercial vehicles like trucks, buses and pick-ups as well on passenger car market.
On manual transmissions is very common to use helical gears to transmit torque. Some of typical failure modes of these gears are tooth breakage, pitting and scoring.
The objective of this paper is to present a case study of helical gear scoring issue on manual transmission and the design changes implemented in order to solve it. This material also shows the ultimate consequence of scoring problem on gear life and the co-relation of the part heat treatment case depth specification on this failure mode.