I have about 7,000 miles on my 08 xB and I've been having some problems with it lately. When I am slowing down, at about 5-10 mph the front left side of the car (possibly the tire) makes a thump sound and can be felt through the floor.
When accelerating there is, again, another thump when i just start moving.
The problem appears after about 10 minutes of driving, is somewhat intermittent, but is more likely to be replicated when turning the steering wheel half way to the left.
Today i came home and started tugging on the front left wheel, after about 3 hard tugs, I heard the sound from the outside of the car and it was pretty loud.
What could this be?

 

Mine too with 5000 miles on the car..its a clunk but i feel it more when I hit a bump. It sounds like something is loose, Im going to have them look at it on my 2nd check..AJ

 

Maybe your shock and strut bolts are loose. I saw in the tC forum that a lot, and I mean a lot of tC's nuts were loosening on the struts and shocks. Right where they attach to the car if I remember right.

 

I think I've tightened those, but I'll check one more time. I've taken it to a shop and had the guys look at it and they tightened everything under the car, to no avail.

I'm starting to think that the CV joint may have gone bad...which is weird at 7000k.

 

Since it's a new design there could be a lot of little things. Either way, if it's something you absolutely know it shouldn't be doing, you can keep taking it to the dealership even though they keep saying they can't find anything, and if your the kind of person that can do this, get mad and start saying you'll call Scion corporate and ask them why a supposedly "properly trained" dealership cannot fix a simple problem like this and why a brand new car is having problems and mention lemon law and all that stuff. Bring a friend, make a fun day of it all.

 

Is there any type of clicking noise as you turn?

 

Check the motor mounts.
Kiiski

 

Nope. Tested that myself last night. Did about 10 circles each way, completely silent. I'm starting to think it might be an engine mount now lol.

 

Have the dealer option intake? Just saw that about the xa/xb version that the mount the intake is attached to the same bolt as the motor mount, so after a little while the intake mounting plate gets squished flat due to the weight of the motor and the bolt gets loose, and falls out it you wait too long to notice.

 

Nope, just the stock air box.