The trouble you have is you should not be in 4 Low where your wheels can't slip. You are on concrete and asphalt and there is nothing giving there, so you are loading up the wheels with the extra weight behind pushing, and making turns.
Now I don't know what you have for 4 low, but I know I have Warn hubs in mine, and the joy of that setup is you can set the trannie for low range, but not use the front wheels unless you put the hubs in.
If yours works like that, go for 4 low and you will be handsomely rewarded I bet.
If you have to use all 4 wheels on the way down the straight stretch, go for it, but I would avoid turns and just bring it to a stop and then go forward again in 2wd
