Good evening all. Transmission problems ensue:

I have a '00 E53 4.4 with 130k. 2nd owner, the trans (ZF5HP24) has never been serviced. It has always ran beautifully and has had many of the suspension, electrical, and cooling problems covered on this site. It has been otherwise reliable and an awesome car to drive...for my wife. She drives it and loves it, I fix it!

So after coming back from a roadtrip, I got into town and went around a corner where it downshifted, and revved like it was in neutral when I accelerated, and then clunked into gear. First time for any abnormal shifting. Upon downshifting, it has done this predictably ever since then. It upshifts on full throttle perfectly. It takes a moment to find 2nd gear when downshifting from 3rd. It freerevs and then slams into gear if there is much load. It has gone into trans failsafe a couple times. It is much better in tiptronic, just takes more to replicate condition.

I took it to a supposed reputable indy shop, but was treated like I was at a dealer.
They pulled these codes:

1) (033) 21 Function, camshaft control, inlet, bank 1
2) (049) 31 Symptom, gear monitoring
3) (053) 35 Gear monitoring 3 (P0733)
4) (052) 34 Gear monitoring 2 (P0732)

The fluid was supposedly low, so they added a liter and downloaded updated software for it, but to no avail. They just told me I need a new transmission. It has worsened considerably since then. This has all happened in the last week.

I have researched this forum and others for days, have not found many correlating circumstances, and few with the same fault codes. After reading numerous threads, these are the various ideas I've come across so far:

1) TPS sensor
2) Speed sensors in tranny ( I assume they mean the 2 pulse generators)
3) Difference in front/rear tire diameter ( my rears are a bit more worn)
4) Dirty wheel speed sensors
5) Trans fluid pressure switch assembly
6) Gear position switch on side of tranny ( neutral position sensor)
7) Output speed sensor (not sure if that's the same as #2)

We love this car! and I prefer doing things myself, so I need some awesome wisdom from this great forum. Thanks!