[ODE] wheels attached at the wrong spot

[Ian McMeans]

Here are two pictures that I think illustrate my problem:
http://www.imageshack.us/my.php?loc=img2&image=normal1.JPG

This is how my car looks with no gravity. Once I press forward and the
wheels start spinning around their centres (IE in the normal way wheels
spin), my car looks like this:
http://www.imageshack.us/my.php?loc=img2&image=after1.JPG

It appears the pairs of wheels are revolving around an axis at the centre of
the car body, and the car body is spinning in the opposite direction (I
guess it's preserving linear momentum). Has anyone run into this weird issue
(or understand why it's happening ot me)? I'm using hinge2's, and the each
wheel's joint's anchor is position at the centre of the wheel.