When you put your car in gear, there should be minimal noise. The transmission should engage easily, and you should be able to drive without any effort. If you’re hearing loud noises when the car is put in gear, it could be one of several different problems depending on the type of noise in question and when exactly you’re hearing it. It may not even be related to the transmission.
How this system works:
When you put your car in gear, it puts a load on both the engine and the transmission. When you press the gas, that load changes. For this reason, engines and transmissions have mounts. These mounts cushion, support and secure both the engine and transmission, ensuring that the loading doesn’t translate into loud clunks, thunks, bangs and other abnormal sounds.
In addition, a number of things must happen when you put your car in gear (these will vary drastically depending on whether you’re driving a car with a manual or an automatic transmission). For instance, with a manual transmission, you must press in the clutch pedal, which engages the clutch and allows you to shift gears. If the clutch is worn, you may hear a grinding or screeching sound here.
In an automatic transmission, things work a little differently. There are clutch plates throughout, as well as bands that connect each gear. If either the clutch plates or the bands have suffered wear, it’s possible you’ll hear noises when the transmission changes gears.
Common reasons for this to happen:
Low Transmission Fluid: The most common reason for any transmission-related problem is low fluid. Your transmission requires the right amount of fluid to operate, and to protect internal components from wear and tear, heat and friction.
Failed Motor Mount: Another common cause of hearing a noise when putting your car into gear is a failed motor mount. Different makes and models use different types of mounts. Some are little more than rubber blocks, while others are hydraulic units. In either instance, a failed mount (or a missing motor mount bolt) will create a very loud noise when you put your car in gear.
Failing U-Joint: If you have a rear-wheel drive vehicle, the problem might not be with the engine or transmission, but with the drive shaft. A bad U-joint can cause a very loud sound when putting the car into gear. Play in the joint allows the shaft to flex incorrectly, causing noises and vibrations.
Worn Clutch: If you have a manual transmission, it’s possible that the clutch is worn out. This would make a screeching/grinding noise when attempting to put the car in gear.
Failing Pilot Bearing: This problem is only pertinent to manual transmissions, and only when engaging the clutch (pressing the clutch pedal in).
Failing Throw Out Bearing: If you hear a noise from your manual transmission when releasing the clutch, it could be a failed throw out bearing.
What to expect:
A professional mobile mechanic will visit your home or office to inspect the noise your car is making when putting it into gear. The mechanic will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
The mechanic will need to crank the car, and then put it in gear to verify and duplicate the noise. Based on this test, the mechanic will either have a diagnosis, or will need to inspect other components of the vehicle to verify their condition and operation. The actual steps taken will depend on the type of noise you’re hearing.
How important is this service?
Unusual noises when putting your car in gear should always be cause for alarm. It might be something relatively simple like a failed U-joint, but it might be a sign of transmission damage, or a failed motor mount, both of which are serious problems. One of our professional mechanics can diagnose and repair the problem for you.