4L80E holds 1st gear too long

[topfuel67 0]

I just bought a 2001 Suburban 2500 2WD with the 8.1L and the 4L80e.  She came from an impound auction and the PO had the steering column hotwired and busted.  She had the check engine light on with 4 codes for the transmission.  One of them was p1860 and I forget the rest.  When driving in D she starts off fine in first gear, but holds it to about 4k rpm or until you just lightly ease off the gas.  She also hesitates just slightly engaging into reverse.  So I read that a faulty ignition switch could trigger those trans codes, so I replaced the column and put a new ignition switch in.  The check engine light is gone, but she still does the same thing holding first.  All other gears are fine and she shifts through the other gears no problem, still hesitates engaging reverse though.  I changed the trans fluid and filter, still same exact thing.  

I just bought a transmission pressure tester and will check that.  If anyone has any suggestions on what to look for I would appreciate it.