Finally got the UUC bushing installed by the dealership. Lucky me I was able to convince them to install it under warranty as this would be the 5th differential on my 04 V. Got a call from the service advisor suggesting I replace the diff fluid with the GM fluid and additive as they noted the diff whining. I denied the service as I just replaced the fluid with Royal Purple about 500 miles ago. On the drive home I was a bit disappointed that the clunk is still noticeable. Just a slight improvement between shifts. The whining is actually louder than I thought it would be particularly at cruising speed between 60-80mph and acceleration. I guess this would be a good time to try AMSOIL Severe Gear 75-90 and Slip Lock. Hoping it could quiet down the diff a bit. Next plan is to replace the stock motor mounts with the UUC mounts. I'm a little hesitant as my stock mount were just replace about 15,000 miles ago. Hopefully the mounts will further reducing the clunking.