Just traded my 05 3/4 ton 2 wheel drive for an 07 1 ton dually 4X4 and I would like to know what is the highest speed I can drive in 4X4 high, without tearing anything up. Thanks, Sonny T

 

I wouldn't go any faster than 50-55mph. If your going that fast, you probably don't need 4 wheel drive.

 

I don't think it really matter. Everyone who drags there trucks do it in 4x4 and can get 100mph in a 1/4

I wouldn't try shifting into 4x4 at a high speed though.

 

I think the book says 45 or 55 max.

 

shifting to 4x4 is 50mph max, however as long as both tires are rotating at the same speed you can go as fast as you want. . .where the problem exists is when the tires rotate at different rates and the chain in the transfer starts to bind up. over time it will stretch it out.

I'll use 4x4 on occasion on the highway in heavy rains to keep me going straight, but I'm only doing 40-45mph.

 

One huge problem comes up when you try to turn at higher speeds. When in 4x4 the tires need to be able to "slip" in order to compensate for the front end being locked in. Remember, there are no spider gears in the front end, that's why the wheels can chatter if you take a turn in 4x4 on dry ground.