Most vehicles are manufactured with manual transmissions as a standard feature, with automatic options offered as an upgrade. Drivers who opt for cars with manual transmissions should know what to pay attention for when it comes to keeping their transmission systems in good health.
There are a number of issues that can crop up with a stick shift setup, and most of these are accompanied by specific sounds. You should first check the transmission fluid if continuous grinding or whining noises occur when the engine is running. Fill the reservoir to the marked appropriate level with the right grade of transmission fluid and see if that eliminates the noise. The owner's manual will be able to point you in the right direction when it comes to choosing the right fluid for your particular car.
If you hear a rattling sound coming from the rear of the car when the engine is running at a low RPM, the fifth gear may be to blame. Not all cars have a fifth gear, but in those that do, the gear may have more room to move around than other gears. Using high-quality gear oil can help to eliminate or at least tone down the noise.
Sounds emitting from the drivetrain may also be related to transmission problems. In most cars, the majority of drivetrain components are located near the front axle. Sounds coming from the drivetrain can reveal a number of transmission issues.
When the engine is idling and you have your foot on the clutch, a high-pitched squeal or a rough grinding sound may be indicative of worn or damaged throw-out or input shaft bearings. If you hear noises when the car is in neutral, the engine is idling and your foot is not on the clutch, this could be caused by several different issues. Worn bearings will cause high-pitched sounds when the transmission is in this configuration as well. High-pitched sounds can also point to faulty torque tube bearings.
When the bearings wear out, the only way to replace them is to dismantle the transmission and rebuild it. In many cases, it can be simpler and more cost-effective to replace the system.
If you have difficulty shifting or getting the clutch to stay in gear, the clutch disc or pressure plate may be worn. This could also be a sign that the synchronizers, which are designed to make shifting transitions smoother, are wearing out.
You can also check the oil level. If it is low, you may have a leak and the fluid might have gotten into the transmission housing. If the clutch plate is coated in oil, it will be difficult to create friction between the disc and the flywheel. This can cause the clutch to slip and the engine may stall.
On the other end, the clutch could be sticking or dragging. This may be due to too little lubrication, air in the transmission fluid lines, a faulty cylinder or a maladjusted clutch linkage.
Leaking transmission fluid can be at the root of transmission problems. There may be too much fluid in the system, causing overflow. The transmission housing could be cracked, or bolts could be loose or missing. The best way to check for leaks is to put a piece of paper under the car where the transmission system is located and leave it over night. In the morning, check for any signs of leaking fluid.