Hi guys first post.

Okay so so I bought this 2006 530i from auction and it didn’t have a key. I went to bmw and purchased a key and the battery was completely flat, jumped the car and it ran rough at first but that’s because it hadn’t been turned over in who know how long. Eventually it calibrated and started to run better.

Now to the good part, I drop the shifter into “d” and it clunks down like it is in gear and on the dash it is in “d” I let go of the brake and it goes forward a few inches and stops (it’s facing the street downhill in the driveway) I then step on the gas and it freely revs up. Throw it in reverse from there and “r” is displayed on the dash. Lurches forward again and locks up free revs when gas is applied. I shift into the steptronic gears and same thing, free revs when gas applied. Trans pans is flawless no cracks or anything and no codes relating to transmission shown.

Any gurus have any experience with this behavior or any further advice would be fantastic. This is my first bmw and have read bad batter could cause this but I swapped battery with my dad’s e60 525i and coded it to my car with the tool he has.