New Auburn Posi, noise when turning

[bark3rd]

I just had a new posi unit put in, and it has been a nightmare. The tech at the local tranny shop is a moron and now I have bad grinding noises when turning hard left or right (especially at slow speeds). Now I have to take it back again and I dont trust them. I bet they can stop the grinding but what if my new $500 Auburn pro has been damaged? I dont think they will tell me. What would you do? This all started when I had a bunch of play in the stock posi unit and I was told the posi unit needed to be replaced. The play has been eliminated, but should I have needed a posi unit at 11k mi? I've got about $850 into this so far! Help!

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Black 2000 GT,5 spd,17" wheels,4:10's, HPM Megabite Jr LCA's, Flowmasters, Steeda pulleys, timing adjuster (11 deg), K&N filter, Nitrous Express w/purge (75shot currently),NGK spark plugs (lower heat range than stock plugs), airbox silencer removed