Vibration in 2017 Highlander LE, 4 cyl, 6-speed transmission: what can it be?

Maitemia

The vibrating started about 9 months ago but only I could tell - my wife came to notice about 3 months ago after it progressively had gotten worse. It does not vibrate while in park, neutral or in drive while stopped at a red light. It only vibrates when driving, initially only between 30-45 mph - now also 55-70 mph. It stops vibrating when you accelerate. I thought it was something to do with suspension, front-end, motor supports, etc. Initially mechanics would say change this ball joint or that bushing. Recently a bonafide and trustworthy mechanic is telling me that it is the transmission. Since the Highlander has 145k miles and has never had transmission oil change (my bad!) he is recommending that we only do a tune-up (change some oil - not all - as well as filter). He believes it is the right move before making any other drastic move. He is also thinking of doing some software update that might help.

Has anyone had this issue before?

2017 Toyota Highander LE, 4 cyl, 6-speed, 145,000 miles - no accidents

thecardoc3

Some vibrations can be difficult to figure out what they are by feel alone. What you need to do is change some of the possible sources to see if you can make the vibration change. It's good that you can identify a specific vehicle speed that it occurs under, have you checked to see exactly what the engine speed is at the same time?

One of the things that I would do once I feel the vibration at the speed mentioned would be to manually shift the transmission into another gear and change the engine speed and see if I can tell if that makes a difference in the vibration. Once you have shifted into a different gear now change the vehicle speed to one where the engine speed was the same when the vibration occurred and see if the vibration is more related to vehicle speed versus engine speed.

Another trick to employ is to measure the frequency of the vibration. There are apps that you can download on your cell phone that take advantage of the motion sensors in the phone. Once you have installed one of the apps, turn it on and set the phone down on a solid surface in the car. When you feel the vibration occur, save the data on the phone. Now we need to figure out how fast different components are moving and see if the measured frequency on the phone matches something that is moving on the car like an engine mounted accessory, the engine (crankshaft), the front and/or rear driveshaft, wheels and tires or some other component. One possible vibration source that wouldn't match any of those would be the torque convertor clutch inside the transmission. If that becomes likely coming up with a way to disable and re-enable it could reveal if it is the source of the concern. If that is the case, then changing the transmissions fluid and using an additive can help in some cases.