Q: Knocking/fluttering in rear end

asked by on

I have a 2010 GMC Acadia. Last Friday my car didn't feel right. Thought I had a flat because of the fluttering sound in my rear end. Later that morning I Ended up getting a flat and a screw in the other tire (both passenger side.) they plugged the front and replaced the rear pass. No more noise. Fast forward to this Friday night noise is back as is a clunking sound. Took it to get looked at. Suspension is all good. They suggested could be the drivers rear tire is so different in tread depth that it is tricking the speed sensor to fool the rear differential. They suggested I change the rear tire and that should fix it. Asked if I was doing any further damage driving it. They said no. I drove it home yesterday and out today around town. Fluttering is worse and noisier. I'm sure it has something to do with the rear diff from everything I have read. So my question is... Any suggestion of next step? Will tire make that much of a difference? I have owned the car since 88000 and have no record

My car has 112000 miles.
My car has an automatic transmission.

Hi and thanks for contacting YourMechanic. If you have a limited slip differential, then having 2 different size tires on the axle will cause the limited slip differential to make this noise. Eventually, the limited slip will stop working and your vehicle will then drive normal with burnt clutch material in the differential oil. I suggest putting the odd size tire on the front of the vehicle and putting a regular size tire on the rear. If you would like to have another local expert inspect the car in person, a qualified professional from YourMechanic can come to your car’s location to pinpoint the proper fix.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Knocking/fluttering in rear end

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: When I go 60 or 70, my truck shakes

Hi, thanks for writing in. If you lift the tire off the ground and can move the tire side to side and top and bottom in and out, then the wheel bearings are bad or loose. If you can only...

Q: My park assist is turned off - how do I turn it back on?

Hello - most often, this message appears when something blocks the rear parking assist sensors on the rear bumper (dirt, snow, bumper stickers, trailer towing gear, etc.). Wipe off the sensors with a damp or soapy paper towel, drive forward...

Q: Pressing on gas pedal, car loses power - 2010 BMW 335d

Excessive soot and carbon (pre-maturely) from the EGR system is most likely clogging up the intake system, throttle body, etc. Although the dealer is supposed to be responsive, if you are having further issues, or would like a second opinion,...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.