I had originally planned on using a Powertrax locker, but when I went to install everything it didnt fit. Came to find out the rear was a 7.5. The cool thing about the Powertrax locker is that it uses your stock carrier, so you dont even have to pull it out. Just rip out the guts(clutches, Spring), and throw in the locker. Its that easy, but when I found out I had to swap rears, I knew I'd need a new carrier and gears and everything so I returned the locker and bought the Auburn. I figured at this point I was over my head since I was short on time, and Id have to get a rearend and COMPLETELY rebuilt everything. I just let Pro Gear do the headache work for me and Im happy for that.