A humming or whining noise from the gearbox at highway speeds often points to worn bearings, low fluid, or a failing torque converter. Here’s what to check and whether it’s safe to keep driving.
Common Causes of Gearbox Humming or Whining
If your Toyota Land Cruiser 100 makes a humming or whining noise from the gearbox when cruising at highway speed, the most likely culprits are worn input/output shaft bearings, low or contaminated transmission fluid, or a failing torque converter. The noise often changes with engine RPM and load — listen closely to see if it gets louder when accelerating or when coasting.
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