Daniel, do a search on the subject, right upper corner of the screen. I am in the process of replacing the differential mounts now. Well, actually I am waiting for a tool (expensive) to pull the differential mounts (cheap) from the frame. Without this tool I don't see how it could be done. You have to lower the differential to gain access to these mounts.
As far as the small changes in direction check your rear suspension links/arms. Very common problem in these vehicles, especially if they are originals.