I am going to make a "guesstimation" here and try to propose what may be going wrong.   The way it appears to me, ArmA's wheels "snap" to surface. Meaning that if suspension of a given wheel is not fully extended, it is "snapped" to the surface (sticky). If the vehicle moves over a hill, and the front wheels extend their suspension to maximum extension, then the wheels do not extend further, but they still "seek" to snap to the surface of something.   This method always works fine when there is a sudden increase in distance from vehicle hull to ground, because the wheel will simply "detach" from the surface, however it seems this has a really adverse effect when the opposite happens - when the distance suddenly decreases.   When a tank traverses it's hull sideways, the roadwheels will hit some curb/stone/object and immediately, due to wheel/terrain "snap" it compresses the suspension in a nanosecond. This means that the force is happening at light-speed, transferring to the hull, and then launching the tank (this is ground control to major Tom, there's something really wrong).   To me, this seems to be the reason. There is no "inertia" in arma suspension. In real life, the wheels are heavy, suspension is heavy and so if you try to compress the suspension, it will happen over time, not instantly. Sometimes it actually seems that ARMA 3 does not have physical suspension, only visual. Meaning that the 3D geometry model that acts with the surface is not really using suspension, but it's only animated for visual appeal. I may be wrong here, but that's how it feels some times.     I found a video that strikingly resembles this theory of no "arma shocks". It's made by someone in algodoo, and shows a three-wheeled vehicle with suspension, and one without. Just look at the one without suspension as it hits a tiny "bump", and think about what you see in ArmA :)   At 0:09 the first vehicle with suspension hits the small bump, look what happens to the second one immediately when it hits the bump:     This is very much resembling what we see in arma. Now imagine that you "spawned" the vehicle without suspension so that the wheels where clipping through the object, but standing on the surface. The result? If the vehicle wheels are designed to "snap" to the surface, they will instantaneously travel the height of that object in virtually an instant. Leading to X amount of m over no time.     A quick example of what this would look like. If a tank in arma, stands beside a curb that is 10 cm tall (0.1 meters). Imagine you traverse the track sideways so that the wheel "snaps" to the top of the curb as soon as it touches it. Let's say the time it takes for the wheel to perform this snap takes 0.01 seconds. 10 milliseconds.   Then the speed becomes 10cm x 100 milliseconds = 10m/s.   10 m/s = 36 km/h which would definitely launch the vehicle upwards in a small jump, if it does not properly absorb/dampen the shock.   Now what if the distance increases? Well the speed increases substantially. I don't know how many "ticks per second" the arma simulation runs at, but we can assume this is a constant. So then varying object height should vary the results.   Poles seem to fling things to infinity and beyond, while small stuff seems to make vehicles jump.   Have a look at this Quad ATV vs box. Although provoked by "moving the box", it seems highly related.     Seems again that the game is trying to check if the vehicle should be ontop, or next to the object it is "half-way" clipping through. It suddenly decides "oh, you are trying to be on top of the crate" and transports the front up there in a single "simulation tick" then we have Liftoff!   Like I said, I'm not 100% sure what's going on here, as I have not made any AddOns in O2 or tried to make vehicles in ArmA, but it does look to me that the problem that is causing this has to do with suspension, and wheels snapping to terrain/objects. The wheels should "transition" from the previous surface height, to the new object height over time, not in an instant. That would soften the effect some, and secondly the shocks should compress fast enough so that the force is not translated to the hull of the vehicle, subsequently launching it into space.   I'm just adding my take on it and hoping it may lead the devs to the clue of what is going on.     PhysX? More like SpaceX :)