I have a vehicle set up using DarkPhysX, but the wheels spin sideways, along the y axis.
phy add vehicle body 1, 156.465484, 109.329414, 386.322662, 0, 25, 0
REM Front Right
phy add vehicle wheel 1, 3, limb position x(1,3), limb position y(1,3), limb position z(1,3), 10, 50, 1, 1
REM Front Left
phy add vehicle wheel 1, 5, limb position x(1,5), limb position y(1,5), limb position z(1,5), 10, 50, 1, 1
REM Rear Right
phy add vehicle wheel 1, 2, limb position x(1,2), limb position y(1,2), limb position z(1,2), 10, 50, 0, 0
REM Rear Left
phy add vehicle wheel 1, 4, limb position x(1,4), limb position y(1,4), limb position z(1,4), 10, 50, 0, 0
phy set vehicle static friction 1,0.0
phy set vehicle dynamic friction 1,0.0
phy set vehicle max motor 1,1000
phy set vehicle steering delta 1,0.25
phy set vehicle steering angle 1,1.0
phy set vehicle auto 1,1
phy set vehicle suspension spring 1,0.0
phy build vehicle 1
