blykins - I have a 9in. Auburn Detroit locker. When it was new with a new ring and Pinion it was fairly tight but after about 10 hours of use it loosened up. Try this. Jack up the rear end of your car with the wheels on, break the driveshaft to the yoke, and see if you can turn the wheels by hand at the yoke.(about 5 lbs torque) On my car you can, with the rear end hot.
Of course there is more to this simple test than meets the eye.
Like brake drag, wheel bearing resistance and so on. Generally the easier it is to turn the rear the more power you car will transfer to the wheels, aka racing 101.
With the driveshaft off and one wheel on the ground I can turn the other wheel at the lug with about 10 lbs of torque on a torque wrench, to simulate going around corners.
Other stuff, don't run any trick gear lube in a Auburn, just straight 90 wt. dino goo. And change it after about 20 or 30 hours of use on a new break-in. I tried red line
synthetic on my first change and started to get ring gear wear. So I switched back to Kindall dino lube and I noticed it was also quieter, esp. going around corners. click,click,click,click.
I'm using pro gears BTW. And I can't tear the da#n thing up either.
cobrashock