I have been running 33's on a Dana 35 for a few years and just blew up my first axle. Moderate climb on broken rock/gravely surface. Was in rear wheel drive (front wheels not pulling). This was with 30 spline alloy axle and mtg replaced it on warranty but still I think it was not a tough hill. I am going to go to D44 or 8.8 axles when I can. Everyone warns about D 35 betting weak and I am now a believer
Good luck