4L60E weird shift and speedometer issue

[Goats86]

I have a friend with a 2005 5.3/4L60E. Several weeks it started having odd shifts(late, hard, etc). Then this am the speedo was reading about 80 mph when she was only driving about 30 and read over 100 when on the highway. It sounds to me like the VSS may be going bad, giving the ECM bad info and causing the odd shifts and now speedo issues. Has anyone had this issue or be of guidance where to look? Thanks in advance.