Well then! Its just like a gun, you name a joint what you want it to do.
No, the mount name for a vehicle is different from a gun's mount name
For a vehicle, place a joint, go to the 'Joints' tab, double click the joint you placed (Example: joint1), and once it's red (Selected), replace Joint1 in the text box below the Joint list with mount0 then hit the Rename button next to it, then deselect the joint
Mount0 = Driver mount
Mount1 and higher are the rider mounts
For wheels, place then deselect a joint and repeat this three more times to have 4 new joints, put one joint where you want the front left wheel to be, then name it hub0, move the next joint to where you want the front right wheel to be, and name it hub1, move the next joint where you want the back left wheel to be and name it hub2, then move the fourth wheel joint to where you want the back right wheel to be and name it hub3
You should now have your driver mount, and the wheel mounts and if done correctly, none of them should be connecting to each other