i just purchased an 06 Lexus IS250 AWD w/136k miles on it, and today while making a u-turn at about 25-30 mph it made that grinding noice.
Another instance where I experienced something similar was while driving a 2015 Nissan Frontier on 4x4, it would make some kind of grinding noise//slipping feeling while making turns.. as if the wheels were sliding on ice.
Last time I experienced something like this was on a 04 Toyota Corolla S when moving forward from a stop, it would make a grinding noise too. On the corolla it tuned out to be bad engine mounts; after replacing them with OEM mounts, the grinding noice was gone.
If you find out what the issue is, please update this thread.