Vista Cruiser Mini on 2007 Dodge Sprinter 3500 chassis

[Mebryant]

Have a 2008 GS Vista Cruiser Mini on a 2007 Dodge Sprinter 3500 chassis. Trying to troubleshoot a noise that began on trip last week. Sounds like a screech coming from rear driver side that is rhythmic with increasing speed. No light on dashboard indicating something is wrong. Checked brakes...all fine. Removed hubcaps to see if that changes anything...no. There is what appears to be old lubricant on wheel hubs. The garage that is working on it is having problems nailing down the cause of the noise. Any thoughts out there?

Appreciate any thoughts...