Does everyone run their new setup on jack stands for 10 or 15 mins. before running it with a load? That is what my rear end guy always told me to do. You should be able to wiggle the driveshaft or tire back and forth a tiny bit before it starts turning the whole shabang. If it has no backlash I would be a little suspect. I don't see a problem with the spool on the street either. I would imagine you would run some sort of ET tire with it which will slip good enough in parking situations where turning might be tight. Redline shock proof gear oil is your friend, 2 quarts is all it takes.