Shimmy, shake, jiggle, when >50 mph and accelarating

[1004ron]

My 2017 Sport is very well maintained with 107K miles on the clock.

 

It runs very smooth but has a slight drive-line gear whine when above 50 mph and still sending power to the rear, but I can live with that.

 

More concerning is when on the interstate cruising at speeds above +- 50 mph and accelerate fairly hard, I can feel a shimmy shake which feels like an out of balance wheel, but subsides as soon as I let off the accelerator.

 

Next weekend I'll be doing a lube service including the PTU, and wanted to hear from you folks what I should inspect to identify the cause of the shimmy shake.

 

I'll also get the wheels balanced, but doubting that this is what I'm feeling.

[Biker]

If only under acceleration, I'd look closely at your tie rod ends. One or both could be a bit worn, causing a wheel to wag back and forth like a shopping cart wheel. (Exaggerated, but you get the idea).

[1004ron]

My wife's BMW X5 has two of these hydraulic engine mounts, and I have replaced one of them - it leaked oil and was compressed.

 

The Edge Sport has only one of them on the right side and mine looks compressed/collapsed - see below photo - hows this compare to yours?

 

If I get off work early enough tomorrow I'll get it up on four jack stands and inspect everything underneath - I always inspect the drive-shaft rubber boots when I do oil changes and they're all in good condition with no lubricant leakage.

[1004ron]

Compared to the height of a new mount, mine looks compressed.

 

[omar302]

@1004ron

 

I looked at mine and it looks like yours. I cannot determine if it's compressed or not. The rubber "flap" circled in the screenshot below is not compressed and can be moved. It seems like it is there to prevent metal to metal contact on high engine movements or vibrations.

 

Also there is no oil leaking and no vibrations.  I only have a clunk during throttle tip in after coasting, but I don't think it is from the mounts. 

 

 

[1004ron]

Thanks omar302

 

That rubber flap on mine is also not compressed, and no oil leaks to be seen - I'm guessing the mount is still good.

 

Today I got it on four jack stands and checked everything out on the underside, drive shafts, all engine and transmission mounts, prop-shaft as best I could see and feel.

 

I did an engine oil change and PTU change while I had it elevated - only been 3K miles since I last changed both.

 

First pulled the PTU fill plug and nothing dripped - was concerned that trans fluid was leaking by the seals, but that's a non-issue now.

 

The only thing done different was I rotated the wheels - all four tire wear is even, fronts same wear as rears.

 

I then took it on the interstate and could not invoke the shimmy again, so I'm suspecting one of the wheels that was on the front needs balancing - will be going back to Discount Tires for all four balancing.

[Eagle619]

Any information regarding that slight drive-line gear whine?

 

I have a 2013 with 155k on it, and just started hearing this. I would appreciate any information anyone can offer.

 

Thanks!

[1004ron]

I haven't done any further research on the gear whine.

 

Just last week I changed the PTU fluid and the magnetic plug was clear and the oil looked good.

 

Sometimes the AWD keeps power to the rear at speeds greater than +- 50 mph and that's when its more prominent.

I back off the throttle and when the power goes to the front wheels only it seems quieter.

[1004ron]

Got the wheels balanced at Discount Tires, and as expected they tried hard to use the opportunity to sell me a set of new tires - I declined and went with the free balancing.

 

They reported minor balance weight changes.

 

Haven't had the shimmy shake, but if it happens again I'll do more searching.