From experienced automotive professionals to the average driver, we’ve all heard mysterious sounds coming from our cars, but should we worry? The simple answer is yes. Automobiles are becoming increasingly complex, so it’s important to ‘listen’ to your vehicle, and to have a qualified and trusted mechanic diagnose and resolve any issues. That said, when you hear a recurring sound that causes you concern, understanding how to explain that sound and any symptoms can provide your mechanic with valuable information that can assist them in reaching a diagnosis more quickly. When these mystery sounds occur, pay attention to your engine speed, vehicle speed, engine load, and transmission range, as these are key indicators that your mechanic will want to know. And, equipped with a bit of knowledge, you the consumer can also stand to save a lot of time and money on repairs.
Some sounds emanating from your vehicle may be your automatic transmission warning you that something is seriously wrong. Here are five common transmission sounds that are worth looking into:
A high-pitched whining noise that gets worse in reverse could mean that you have a clogged transmission fluid filter. A great test for a clogged filter is to raise line pressure without raising engine rpm. You can do this by shifting into reverse. So, if the volume goes up in reverse it indicates a clogged filter. The noise is produced when the transmission fluid is restricted from flowing through the filter. This is not only a problem, but a symptom as well. Fragments from the automatic transmission may have clogged the filter and the source of the debris is the real problem. A clogged transmission filter can also be symptomatic of severe automatic transmission damage.
Whining or grinding noises when driving can mean that the planetary gear set is damaged. Automatic transmissions use a planetary gear system that consists of a single center gear, a large ring gear around that with internal teeth and multiple small gears in between the center and rig gears. This arrangement allows for a variety of gear ratios that can be shifted very easily, but if one part of the system fails, it often renders the whole system inoperable. A failing planetary gear set will cause widespread damage if not corrected immediately. If you hear these noises, you should stop driving and have the vehicle checked for problems.
If your vehicle has a few years on it you may begin to notice harsh or soft shifting or delays when your automatic transmission is shifting through the gears. This may be due to your TCM’s inability to compensate for excessive transmission wear and tear. What’s a TCM you ask? Well, it’s your transmission control module – an amazing computerized device that constantly monitors and manipulates your transmission’s components and adapts as normal wear and tear builds. But adaptation can’t hold wear at bay forever. Eventually wear overcomes the TCM’s ability to compensate and becomes apparent to you in the form of harsh or soft shifting, delayed engagement and shift timing problems.
If you hear gurgling noises coming from your transmission, this is usually an indication that your transmission fluid level is very low. Because there is not enough fluid to fully enter and lubricate the system, the air pockets interact with the fluid to create the sound. The best, and first, indication of low fluid levels is if the transmission falls out of gear when you come to a quick stop or during a hard turn. If a gurgling sound is accompanied with this first indication, your fluid level is dangerously low. Keeping your transmission full of clean automatic transmission fluid is the best thing to do to avoid transmission problems.
- A constant whining sound, one that may change in pitch as you drive, may be indicative of a problem with your torque converter. The best indication of a torque converter bearing issue is that you hear the whining in gear (any gear) while stationary and then the sound goes away in park or neutral. Understanding how the torque converter functions can help identify whether or not a torque converter problem is suspected. Click here for an outstanding animation that is quite helpful in understanding how torque converters operate.
Never ignore the sounds your automatic transmission makes. These could be desperate cries for help and you should take your vehicle to your local ATRA Member Shop immediately before further, and possibly irreparable, damages occur.