The only cautionary note I would offer is that the natural 4WD configuration divides the power roughly evenly between front and back. So your 150 horsepower is split, 75 to each axle. Assuming you drive the same way you did before, driving with one driveshaft is going to double the torque load on the driven axle and line components as compared to driving in 4WD. Putting the whole 150 into one axle is more than it was meant to take. So I'd expect a significant reduction in lifespan on the remaining axle. The risk of u joint or drive axle breakage is also increased if you drive hard.
It works fine as a temporary measure but for the longer term . . . . prob not