Hi,

I have a 2016 Sonata Hybrid Limited with ~143K miles on it. It's developed a slight vibration that's most noticeable in 40-50mph range. Seems to be worse when accelerating. I've been reading about possible causes, and have been trying to check each. Today I checked the inside CV joints where the axle mates to the transmission for play. The passenger side had a bit more than the drivers side. But honestly I'm not sure how much play is too much. I hate to replace the axles if it isn't the cause of the problem. Here is the video I took of the "play" in the passenger side CV joint. I'd appreciate input from anyone with some experience with this.
Play in CV Joint

Thanks,

Gene

 

Hi Gene.
The inside (Inboard) CV joints don't usually give much trouble, but the outer ones take a beating because of the constant turning/steering.

I would suggest you look for a possible loss of a wheel weight, they sometimes do come off and create balance problems that result in speed related vibration, worth checking.

 

Thanks @hanky The outer CV joints have zero play. The tires were just about worn out, and were worn unevenly, so I had new tires installed (computer balanced), and an alignment done early this past week. It made no difference.

Best,

Gene

 

This is what I would do next.
Switch the front and rear tires on one side ,see if any difference, then do the other side and check again. It seems like a lot of work, but now we know for sure wheels and tires are NOT the cause.

By the way, when you state "worn unevenly" , please describe as best as you can because sometimes a wear pattern can point to the problem.

Which are you using when the vibration takes place ? Gas engine running or strictly electric ?

 

Attached are pictures of one of the front tires. The wear is on the inside. Both front tires looked the same.

I have the tires rotated every oil changed and this has been going on for at least one rotation. As I said, I had all 4 tires replaced last week and it didn't affect the vibration.

The vibration is when it's using the gas engine. It isn't a particularly strong vibration. It happens most often when going up a hill. I thought perhaps the engine has lost some power and it's struggling in a high gear going up a hill. But if I run it in sport mode, or even manual shift mode, and downshift, it doesn't seem to affect the vibration.

I did have it at a service station today for something unrelated. They said it has a pinhole in the outer CV boot on the passenger side with a tiny bit of grease around it.

 

The tire wear in one of the photos usually comes from hi speed around corners and/or camber adjustment.
Neither of which produces a vibration.

The reason I suggest switching wheel positions, a rim problem may not show up with some balance procedures,
but the vibration will move to a different area of the vehicle,if that is the problem.
New tires on a defective rim/wheel will not correct that type problem.

A motor mount problem could also get into the picture

 

I would alos suspect warped rotors.. Also bad wheel bearing, ball joint or even bad tie rod.

 

My gas mileage has dropped from a consistent 38-39mpg to a consistent 32-33mpg. Could a transmission issue account for both sudden drop in gas mileage as well as a slight vibration on acceleration? Is there any way to "test" the transmission?

 

I do not believe there is any trans problem.

The clue of a drop in mileage should tell us there is a performance problem with the engine.
What kind of maintenance has been done to the gas engine?

 

New coil packs, new plugs, new air filter, a few cans of seafoam. The drop in gas mileage came on suddenly. After the new tires, alignment, and having the transmission fluid changed. I know that new tires can low fuel mileage a bit, but not that much. This really has me scratching my head. It was not a dealership that changed the fluid. I would have done it myself except disposing of fluid these days is a headache.