I just finished re-installing the rear suspension in my 73. To my surprise it had a 3.42 positrac! I started out just wanting to replace a leaking pinion seal and replacing the control arm bushings. But once I removed the rear end I quickly realized that more work, and money were needed. After checking the pinion preload, which there was none(15-25 in lbs normally) I decided to open the pumpkin. Once inside, all the gears looked in good shape.but my axles were shot. Axle end play was about 1/2" and the bearing surfaces were totally wrecked. I paid $275 for a shop to inspect my gears, shim and install new bearings and axles. I would have done this myself, but I would have to run around and get shims, bearings,seals and a press. I also did not want to have to pull the rear end out again! I disassembled the rear end, and sent it, along with control arms, rear sway bar( picked up at a swap meet) and brake booster and reservoir to get powder coated. If I was going to do this right, I would spend the extra money. I also decided to put disc brakes on and new shocks. Total cost was $1400 for everything except my labor. Once I got my rear end back from the shop, I installed poly bushings and installed the rear end. Here are some pics of the install. I learned a lot during this process an if anyone has questions, feel free to ask.