The "bump" is common to the transmission. Mine was replaced under CPO warranty. Others have had success getting the programming for the trans redone. It has nothing to do with the fluid level, though it can't hurt to check (remember to check at the proper temperature).
xoutpost.com has a ton of threads on this with a lot more detail.
2005 E53 X5 4.4i, Imola Red over black, Sport, Premium, Cold, Hybrid Audio Technology Imagine 6.5's
2011 E90 M3, Melbourne Red Metallic, Fox Red/Black, 6-speed, Premium 2, Heated seats, iPod/USB, Technic harness, JL 6/600