What are the effects of a bad transmission input shaft bearing on a car?
2 Answers
If the transmission input shaft bearing is damaged, it may produce a rustling noise and the temperature may also rise. In severe cases, the shaft may shift, affecting power transmission. Here is additional information about transmission abnormal noises: 1. Abnormal noise from the transmission area at idle: Possible causes include insufficient transmission fluid or deteriorated fluid quality; worn, loose, or damaged transmission bearings; bent transmission shaft; or abnormal gear meshing. 2. Noise in neutral gear: This is usually caused by wear or looseness of the front and rear bearings of the transmission input shaft, or noise from the constant mesh gears. If the noise occurs in all gears, it is mostly due to the rear bearing of the secondary shaft. Severely loose or damaged bearings should be repaired or replaced.
When the axle bearing fails, the car immediately starts making abnormal noises, like metallic squealing or rattling sounds. Normally, you can feel increased steering wheel vibration while driving, which becomes more noticeable at high speeds. Power transmission also becomes uneven, with strong jerking sensations during acceleration, and fuel consumption gradually rises. Sometimes, you might even smell a burning odor. If left untreated for too long, the axle misalignment can wear out surrounding gears or synchronizers, and in severe cases, the entire transmission may require a major overhaul, costing thousands to fix. During routine maintenance, I always emphasize regular checks on the bearing condition—generally inspecting for wear signs every 20,000 kilometers or so, using a stethoscope to listen for unusual sounds, to prevent small issues from turning into big problems.
