I have an 05 2500 6.6 that I installed a rebuilt transfer case in last summer. The original transfer case fried a bearing, it looked as if someone had replaced the rear case half due to the pump rub issue, but it was too late to save the rest of the internals. I bought a rebuilt case from Transfer Case Express in Oakland, Ca. After 2 cases from them I got on that worked and didn't make noise.( That's another story) The case I have now works fine and didn't make any noise until a couple weeks ago. It seems that when it's cold it makes a squealing noise similar to a brake squeal. I jacked the truck up, put it in neutral, and spun the driveshaft by hand and the noise is coming from the slip yoke area where the driveshaft slides into the transmission. I put some high temp synthetic grease on the outsire of the slip yoke and inside of the seal and the noise went away for a few days and is back. Anyone have a similar problem? Is there a better seal to use? Could it be the bushing being improperly installed that is the source of the noise? Thanks guys!