Drive Train Vibration

[dstjohn99]

I have a 2014 Rav4 EV with ~65k miles. Drive Unit was replaced in 2016, around 25k miles. Over the past 5K miles I'm noticing a new vibration that slowly seems to be getting progressively worse.

When driving on a smooth surface, like good asphalt, the car is very smooth. If I accelerate in the 50 - 60 mph range I notice a vibration in the steering wheel as if I suddenly transitioned to a rough road surface. When I let off the accelerator the vibration goes away and it feels smooth again.

This started as barely perceptible but is now perceptible, reproduce able and very slowly getting worse. It is prevalent in the ~50 to 70 mph range and gets worse with heavier acceleration.

Anyone with similar experience? Opinions as to cause?

- Thanks.

 

[jimbo69ny]

I have a 2014 Rav4 EV with ~65k miles. Drive Unit was replaced in 2016, around 25k miles. Over the past 5K miles I'm noticing a new vibration that slowly seems to be getting progressively worse.

When driving on a smooth surface, like good asphalt, the car is very smooth. If I accelerate in the 50 - 60 mph range I notice a vibration in the steering wheel as if I suddenly transitioned to a rough road surface. When I let off the accelerator the vibration goes away and it feels smooth again.

This started as barely perceptible but is now perceptible, reproduce able and very slowly getting worse. It is prevalent in the ~50 to 70 mph range and gets worse with heavier acceleration.

Anyone with similar experience? Opinions as to cause?

- Thanks.

The tires could be out of balance. Have them checked out. That would be the easiest and cheapest problem to fix so lets hope thats what it is.

 

[dstjohn99]

The tires could be out of balance. Have them checked out. That would be the easiest and cheapest problem to fix so lets hope thats what it is.

Thanks, I rotate and balance the tires every 5000 mi. Next one due in about 1000 mi. So we will see if that helps.

 

[jimbo69ny]

The tires could be out of balance. Have them checked out. That would be the easiest and cheapest problem to fix so lets hope thats what it is.

Thanks, I rotate and balance the tires every 5000 mi. Next one due in about 1000 mi. So we will see if that helps.

Not just rotating them. You could’ve lost a wheel weight. They won’t balance tires during a rotation unless you ask them to.

 

[davewill]

The tires could be out of balance. Have them checked out. That would be the easiest and cheapest problem to fix so lets hope thats what it is.

Thanks, I rotate and balance the tires every 5000 mi. Next one due in about 1000 mi. So we will see if that helps.

Not just rotating them. You could’ve lost a wheel weight. They won’t balance tires during a rotation unless you ask them to.

I wouldn't wait for another 1000 miles. I'd have the tire shop check it ASAP. If that's not the problem, then you need to know that soon.

 

[hokiematt]

This is not a tire issue: tires that are out of balance will not improve from lifting the throttle.

Possible culprits: worn tie rod, wheel bearing, ball joint, suspension bushings, CV joint, or internal issues with the motor. The first four you can check by jacking up each of the front wheels one at a time, grab the tire at the top and bottom (then again at front and back) and check for any free play. With the motor in neutral, spin the tire and listen for any noise at the wheel hub. While you've got things jacked up, do a visual inspection of all the suspension components, looking for things like torn boots or an accumulation of grease somewhere. You can check CV joints by making tight turns at slow speed, and listen (windows down) for loud clicking noises. Any reputable mechanic should also be able to check out all these components.

Unfortunately I suspect it may be the drive unit, particularly as you indicate things are getting notably worse in a short amount of time. It could be the bearings going out, and the increase in free play is being heard/felt since tolerances are pretty tight. If you're mechanically inclined, there is a recent post about how you can replace the bearings and seals yourself; otherwise there are vendors that offer this service.

 

[asavage]

Vibration amplitude varies with accelerator input? I'll put five bucks on CV joints or motor mount(s).

No wheel balance or wheel alignment issue will be affected by changing the torque input (accelerator).

Tie rod or suspension bushing issues at 65k? Not likely, unless you're driving in Montreal this winter

But the Tesla propulsion unit puts out a lot of torque that is probably used more often than the ICE version, and I somehow doubt that Toyota uprated the CV joints.

I have 69k on mine, and I notice at 40-60 that when accelerating at more than modest rate, on a smooth road I can feel a vibration whose frequency is close to wheel speed, and it disappears if I back off the accel pedal. I think I've got a bad 'un too: CV joint or motor mount.

 

[jimbo69ny]

Vibration amplitude varies with accelerator input? I'll put five bucks on CV joints or motor mount(s).

No wheel balance or wheel alignment issue will be affected by changing the torque input (accelerator).

Tie rod or suspension bushing issues at 65k? Not likely, unless you're driving in Montreal this winter

But the Tesla propulsion unit puts out a lot of torque that is probably used more often than the ICE version, and I somehow doubt that Toyota uprated the CV joints.

I have 69k on mine, and I notice at 40-60 that when accelerating at more than modest rate, on a smooth road I can feel a vibration whose frequency is close to wheel speed, and it disappears if I back off the accel pedal. I think I've got a bad 'un too: CV joint or motor mount.

Everyone can have their opinions and any one of you could be right. This is an odd case that I personally haven't heard of before. With that said, I'd start with the cheapest option possible, a tire balance check. That might not be it, it could be much worse like other commenters have said, IMHO a balance check is the first thing that should be done.

 

[asavage]

Wheel balance will never change vibration amplitude with torque change. Wheel balance is what it is, it'll shake enough to feel at a given speed, or it won't. Moving the accel pedal will have zero effect.

 

[asavage]

. . . CV joints or motor mount(s).

I should venture here that there probably aren't any conventional motor mounts on the Tesla DU. I was applying ICE experience to an EV situation.

 

[TonyWilliams]

All the usual suspects, of course, including warped brake rotors.

But, the very first thing I would do is check the “usual suspects”. In your case, I would physically remove both axle half shafts, check them for issues with the CV joints (which can be very hard to tell, unfortunately), and then CLEAN THOSE SPLINES, grease them up, and then retorque the axle nut.

Wheel bearings could definitely do this. When the axles are removed, I would carefully spin those wheels, looking / feeling for bearings that aren’t smooth.

After wheel bearings, brake rotors, axles half shafts / splines, your problem is likely in the gearbox.

I have a car with that noise / vibration, and I already know it’s the gearbox, unfortunately. You’re welcome to drive it, and see if it’s the same vibration.

 

[asavage]

New things to learn every day. OK, not only are there motor (DU) mounts -- three of 'em -- but there's even a relevant TSB on the Model S Dual Motor to replace one of the mating parts to the left DU mount mating part ("clevis") to eliminate a vibration on acceleration.

https://static.nhtsa.gov/odi/tsbs/2019/MC-10162295-9999.pdf

SB-19-39-001 Tesla, Inc. June 25, 2019

Replace LH Front Drive Unit Clevis Mount and Both Front Halfshafts

Condition
Older versions of the Model S and Model X LH front drive unit clevis mount contain a bushing that allows the front drive
unit to move side-to-side more than expected during hard accelerations, resulting in excessive vibrations coming from the
front drive unit during hard acceleration. This is exclusively an NVH issue and does not otherwise affect steering
functionality, braking, or acceleration.

Correction
An updated LH front drive unit clevis mount with an improved bushing is available which mitigates the condition. Upon
customer complaint, inspect the vehicle for excessive vibrations coming from the front drive unit during hard acceleration.
If the condition is present, update the LH front drive unit clevis mount and replace both front drive unit halfshafts.

While there's a sort-of analogous mount on the RAV4 EV, I don't know that either the condition or remedy applies to RAV4 EVs in general, but I found this and thought I'd throw it into the discussion. The Tesla mount in the same location is a much more elaborate dual-articulating setup, and it should be noted that the front DU in a Model S isn't even the same DU as ours (which is an adapted Model S rear DU).