Vehicle Wheel physic problems

Hey there!

Im trying to make this work, but nothing seems to work properly.

As you can see in the Video, my plane is always falling and the wheels didnt seem to hold my plane up.
My Setup: Xform → Link the wheels to the mesh → Export with Z Axis up.
Changing the wheels to kinematic will make my plane fly away.

Any ideas what i am doing wrong?


[Physic Simulation][1]