Hey, You NEED to find out the max load your rear axle can carry. 1/2 ton truck axles are built like a cars. All the load is carried on the axle shaft itself. 3/4 and 1 ton trucks all the axle does is turn the wheel. It supports no weight, the weight is supported on the housing itself. BIG difference between the two. Axle shaft overloaded will flex, and eventually break. Not right away, but it will, if continued being used overloaded. I HAVE seen it happen more then one time. Get your rig weighed, checking every axle's weight. Do not exceed! Now with a 3/4 ton load the hell out if it! Wont hurt anything.