OK, so I bought a used rear third member off craigslist and installed it. Put everything in and installed it blah blah blah it drives a lot better now. I thought I was done with the project until I noticed a drip of oil on my garage floor underneath my rear diff.

I cleaned it all up and went for another drive so I could tell where the leak was coming from (I initially thought my RTV job got messed up on the third member install). It turns out the oil leak is coming from the "companion flange", which is wehre the driveshaft bolts up to the differential. So I need to replace the oil seal behind there.

Reading my Haynes manual... it says to use a torque wrench and "slowly turn the pinion shaft nut and measure the preload within the backlash of the drive pinion gear and the ring gear (if the axles and wheels turn, the backlash has been exceeded and the torque figure is incorrect).

So I tried this with just a regular socket wrench (don't have a torque wrench) and the axles and wheels move freely when I turn the wrench. I looked at the pinion nut and there is a tab that has been dented in so that it locks into the pinion shaft itself.

I also don't know really what they are talking about with backlash and all that. Can I just undo that pinion shaft nut, replace the seal, and put a new nut on there??? Or does the "preload" need to be set and all that?

 

This is me answering my own question