Swat van

[LoganFinch]

If the van gets in any type of depth even where it does not touch the bottom of the van it stops and you can't drive it, it is not realistic at all

[TinySimon]

So the vehicle engine positions defines when this happens, and it is handled entirely game engine and it can't be overridden in Lua. The only solution is replacing the model, or recompile it with a different engine position.