The transmission is arguably the most complicated part of a car. Efficiently transmitting the power from the engine to a usable speed to the wheels is a demanding mechanical job, or in the case of automatic transmissions, an electro-hydraulic-mechanical affair. Neglecting maintenance can leave you stranded when it completely breaks down, as it’s almost impossible to fix it on the side of the road. Recognizing and fixing these promptly will avoid expensive repair bills in the future. Here are six signs that you need to take better care of your transmission:
The most obvious sign is what you see on your garage floor. Being the lifeblood of the tranny, automatic transmission fluid (or gear oil for manual transmissions) pulls double duty cooling and lubricating the whole system. If it’s on the ground, it’s not staying where it’s needed: inside the transmission case. If it’s running low or if the quality is past its due date, it will not do an adequate job.
For automatics, a damaged torque converter with worn needle bearings will make audible whirring sounds from under the car. On a manual transmission, grinding noises while engaging a gear may mean the synchromesh is worn or getting there. Constant whirring sounds, squealing while depressing the clutch pedal, or rattling noises as you release the clutch pedal means that a variety of bearings related to clutch engagement needs replacement.
Carrying too much load, excessive friction because of towing, or overworking the engine will cause heat damage to the fluids, thus the burnt odor from it on inspection. If your normal daily drive requires you to go uphill a lot or you tow and carry lots of loads, you may have to modify your system to cope. A transmission oil/fluid cooler will help.
This usually points to problems with malfunctioning sensors, solenoids, or other vital components. But it may also be caused by purely mechanical issues like excessive temperature on the system, low fluid level, debris in the fluid blocking hydraulic flow, etc. It may also mean you need to check your wallet.
Revs are high but speeds are low? That means you have worn out clutches, or in an automatic transmission, poor hydraulic performance. A slipping automatic tranny, even with adequate or newly changed fluid, means that the hydraulic system is not getting the fluid it needs because the solenoids and valves are not allowing for proper flow.
Irregularities, like suddenly falling out of gear into neutral, shifting out of sync with the engine revolutions, or delays in shifting are all related to hydraulic or electronic system failure. On manual transmissions, worn synchromesh, bearings, or even the hydraulic master and slave clutch cylinders will make it hard to shift into gear, or engage and release the clutch.