4Th. Gen 2007 Sport Rear End Rumble at 35-40 MPH

2007 6cyl. 2-wheel drive 4 Runner 122,000 Miles; mechanic checked suspension, universal, tires, transmission and even removed the spare tire a still rumble felt in seats and sound concentrated in the rear of the vehicle. What other possibilities could there be? Motor Mounts are good, AC Compressor is good, new drive belt, new alternator & battery.............Any suggestions as to where to point the finger next would be greatly appreciated.

 

Check rear wheel bearings

 

Define Rumble
Like the front seats are shaking side to side?
Like you hear a growling?
You feel something thru your feet on the floorboard?
Can you give a more specific definition?

 

Rumbling my driver seat to the rear of the car

 

Rumble is only at 35-40 mph? Does it change when you accel/decellerate? Change when you turn? If youre driving and shift into N does it remain or go away? Checked the rear diff? Checked random things like exahaust piping mounts? Exhaust muffler mounts? Heat shields? gas tank? is your bottle jack above the driver wheel well loose in its little cubby?

more description helps, or video if you can too

 

I would bet you have run-out in a rear tire. Jack the back end off the ground and spin the tires or if you're real handy you can jack the rear end up and block the front tires and put it in gear so the rear tires spin and watch them closely. See if one appears to be running out of round like its egg shaped. I see people driving down the road all the time with a tire out of round and its wobbling up and down like crazy. Some folks probably dont know what they're feeling or dont have the money to get it checked out but you can visually see it yourself if you know what to look for.

 

Could be universal joints or drive shaft also.