0.6 Update causing wheel/driveline spaz

Hi, just a quick one for you -

One of the vehicles I'm building was strangely affected by the 0.6 update - as soon as any of the lower gears or reverse are selected, the wheels spaz out, the speedo says it's going several hundred miles an hour even though it isn't moving, and the wind noise effect ramps up. This is without input from the user.

The vehicle, a Unimog 406-alike I'm building, has pretty low gearing to start with but I don't want to increase these particularly. As each higher gear is selected, the spazzing is reduced and the vehicle becomes drivable.

My other vehicles, some of which use more or less the same engine/gearbox code do not seem to have been affected. If anything this update has made them more drivable and stable.

Any ideas?
Thanks

PS: I love you devs, this game just keeps on getting better and better!