knock/thud sounds under the vehicle?

[h&t]

Hi all,

I hear occasional thud sound from under the truck when driving in a straight line at speeds of 50-80 km/h ( up to 50 mph). Sometimes it's one sound, sometime a few, one after another, then nothing for a while.
I think it's at the front.

It's pretty random, not speed specific, nor engine RPM specific.

I don't see anything wrong looking under.
The truck seems to be driving OK.

This is probably not 4runner specific, but I drive 2011 SR5, in Canada, so rust is a potential issue.

Before it happened I was driving on a farm today, it was around freezing with some wet snow on the ground and VERY slippery. My AT tires also getting old.
I had to drive up some steep hills and even in low gear the truck was sliding around.
Basically, driving in 4Low, driving at speed over some bumps (to get up the hills), at one point I put parking brake on (I walked to scout), then forgot to take it off and started driving.

I drove 30 min to get home and parked the truck.

Any ideas what could be making the sound?

Merry Christmas!

 

[DougR]

How long was the parking brake left on? Less than a minute? If so, it's probably fine and maybe not the source of the noise.

I haven't had this issue, so I performed a Google search just to see what comes up. I opened a new webpage to Google and entered "knock thud under 4runner" in the search line. The first hit is this website, toyota-4runner ... 5th gen T4Rs. I then click "More results from toyota-4runner.org" which shows all the relevant posts under 5th gen. There appears to be a lot of possibilities.

Let us know what you find is the source of noise on your vehicle.