Hey everyone I'm wondering what is a normal and safe speed that a person could drive they're second gen 1500 in 4x4? I have a 2001 manual with a 3 inch lift anytime I go over 40kmh on snowy roads I start to hear a unsettling noise from under the truck

 

Probably u-joints that are dry. According to theory, you can shift into 4x4 at up to 55mph.... So, one would think you could drive at that speed in 4x4 as well. Of course, when you need four wheel drive, I would expect that road conditions don't really lend themselves to high rates of speed. Four wheel drive will help get you going, in even the worst conditions, but, it will NOT help you STOP.

 

You can go as fast as you want to in 4x4 high, but you can't use it on dry pavement unless you are going straight, it will bind up when you turn on a high traction surface. Also being in 4x4 does help you stop better in slick conditions, it's been tested and proven several times.

 

On snow, or ice, I really don't care what some study says. In my direct experience, sure, it helps, a bit, to a VERY minor degree, not not enough for me to consider driving any faster than I would in 2wd....... Not to enough to say that it 'makes a difference' either..... Ice is ice, snow is snow.

 

I wasn't insinuating that you should drive faster because you have 4x4, however it does add some extra safety because it shortens your stopping distance.

 

That noise you hear might just be the transfer case working, make sure it has the correct amount of fluid. Why don't you write a better definition of this noise.