The transmission system manages how much engine power is applied to the wheels as you accelerate the vehicle. A series of gears within a gearbox have to shift for the right amount of power to be applied. Most modern cars have automatic transmission systems which shift the gears automatically. That way, the driver doesn’t have to worry about shifting the gears manually as they drive.
Every manual transmission system has an input shaft connected to the engine. When you step on the gas pedal to accelerate, an output shaft transmits engine power to the input shaft. As both shafts turn, the input and output shaft gears rotate as well. This causes the wheels to turn underneath.
The transmission input shaft bearing is a component responsible for sustaining the rotation of the input shaft. It uses lubricating transmission oil to ensure the shaft maintains smooth movements all the time. However, if the transmission oil levels decline too much, it will cause the input shaft bearing to suffer damage. Then you’ll be faced with a whole series of problems.
Bad Input Shaft Bearing Symptoms
Deal with a bad input shaft bearing before it affects the drivability of your vehicle. A few noticeable symptoms will arise as your input shaft bearing loses oil or suffers wear and tear. Pay attention to these symptoms and then replace your input shaft bearing to avoid more severe car problems.
Below are the top 3 symptoms of a bad input shaft bearing.
1) Weird Gear Noises
The transmission shift gears will make strange sounds if you have a bad input shaft bearing. Each time you apply pressure to the gas pedal and accelerate the vehicle, it will put more pressure on the gears and the input shaft. This would cause a defective input shaft bearing to make a loud sound.
You’ll know if it’s the input shaft bearing making the noise if the noise never goes away while the engine is on. You could have the engine idle and still experience these noises. On the other hand, if an idle engine causes the noises to stop, you have a bad output shaft bearing instead.
2) Vibrations
The shift stick will vibrate profusely if you shift your vehicle with a bad input shaft bearing installed. This problem relates to the cause of the strange noises too. As you put more power demands on the engine, the intensity of the vibrations will increase. In fact, you may continue to experience vibrations and noises when the gear is shifted to neutral as well.
3) Gear Slippage
A worn-out or damaged input shaft bearing can lead to a gear slippage problem. That is when one gear slips into another gear within the gearbox, especially when you put pressure on the clutch.
Gear slippage happens because the bad input shaft bearing loosens the input shaft and causes it to move excessively. Then it will throw the gear shafts out of alignment and make it impossible for them to engage correctly again.
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Input Shaft Bearing Replacement Cost
The typical replacement cost of an input shaft bearing is between $400 and $600. It only costs between $25 – $50 to purchase a new input shaft bearing component and $10 – $15 for input shaft seal and around $40 – $60 for gear oil . The exact cost depends on what kind of car you are driving.
As for the labor costs, you can expect to pay anywhere from $300 to $500. The labor costs are usually more than the parts costs because you have to pay about $100 per hour for the mechanic’s time. Since replacing an input shaft bearing is a time-consuming process (it should be pull down and dismantle transmission), that is why the labor costs are a little higher.
Here are the summary:
- Pull down the gearbox (estimate 1.5 hour processing)
- Dismantle the gearbox (estimate 1/2 processing)
- Using puller, remove bearing from input shaft (estimate 5 -10 minute processing)
- Using press machine, fix new bearing to input shaft (estimate 5 -10 minute processing)
- Replace input shaft seal (estimate 2 – 5 minute processing)
- Assembly the gearbox (estimate 1/2 hour processing)
- Fix again the gearbox to the car (estimate 1.5 hour processing)
Cost summary:
- Labor: $300 – $500
- Gear oil usually 3 liter: $38,7 (using Castrol oil)
- Input shaft bearing part: $25 – $50
- Input shaft seal: $10 – $15
Note: The estimate time processing, labor and part cost may vary, depend on car type, model and brand.
The Causes of Input Shaft Bearing Noise
Do you hear odd sounds coming from your input shaft bearing? Below are the two primary causes of these sounds.
1) Lack of Lubrication
The input shaft bearing needs constant lubrication to remain functional. If there is a lack of lubrication, it will cause the bearing to make strange sounds and noises. Add more lubrication or replace the bearing to eliminate this problem.
2) Damaged Bearing
A damaged input shaft bearing will undoubtedly cause these strange sounds to occur. In most cases, a lack of lubrication is the main reason for damage to the input shaft bearing.
But there are situations where the bearing could suffer damage for other reasons, such as a recent car accident or deterioration after several years. The only solution is to replace the bearing immediately.
