My driver side axle broke at the trans side today ,was pulling a pretty steep hill with the trailer loaded and decided to try 4 wheel low ,until today I have never tried the 4 wheel drive to even see if it works. I was straight and pulled up the hill and over the top and came down the other side and it broke and pieces rolled down the hill I never went more than 5 MPH no big strain, I pulled the axle and took the CV apart and put it back in and am down the road. I have had a shudder in the brakes down hill with a load always on all my trucks but this one is first 4x4 and the shudder got worse last 1000 miles and now I believe it was the axle. The truck has 2 in drop spindles any relation ? I have never had a 4x4 so I am green on this one.

Guess if it's not a lift no ideas?

You mean it's lowered 2 inches? My guess is that caused your problem. Your axle shafts are tough and should not fail that easily (unless it was defective).
Take a look at the CV angles with truck sitting at ride height. If they are perfectly straight, this will cause vibrations and waste CV joints. Never run a CV or U-joint perfectly straight. Hope that helps.
Also, you said you already took it apart? Was it dried out inside the boots, or still well-lubed? They should be packed with grease inside.