To get back on topic, I routinely* drive my VX in 4-Low up to about 45 mph. It sounds like the wheels are going to come off at that speed with the engine revving high through the low gearing and the t-case locked and whirring underneath, but it's still within the rev band of the engine. Just make sure you NEVER use 4-Low on dry roads! It needs the poor traction of snow, ice, or dirt to keep the axles from winding up.

* denotes routine behavior in "winter" which has yet to come to the Northeast! And on that off-topic topic, don't whip yourself too much about global-climate-warming-change... the scientific data says that it is happening, but it's only scientific opinion that says mankind is responsible for it. This is a critical distinction, but it is one that seems perpetually lost in all dialogue on the subject. Nature is more likely taking us for a ride than we are taking it for a ride.