Transmission Noise

DIAGNOSIS AND TESTING - NV4500 Manual Transmission
TRANSMISSION NOISE
Most manual transmissions make some noise during normal operation. Rotating gears generate a mild whine that is audible, but generally only at extreme speeds. Severe highly audible transmission noise is generally the initial indicator of a lubricant problem.

Insufficient, improper or contaminated lubricant will promote rapid wear of gears, synchros, shift rails, forks and bearings. The overheating caused by a lubricant problem, can also lead to gear breakage.