If I have this right, your 09 E70 mounts the same six speed ZF auto found in the earlier bimmers [and lots of other makes]. Here is a discussion at one remanufacturer, who says use only the ZF ATF and change at 50k [contra BMW's 'lifetime' story ...]
Common Problems Associated With The ZF 6HP26 Automatic Transmission

Godfather, reading the ETE link in my previous post, I suggest you give them a call. They are in Wisconsin. Perhaps they can identify a nearby shop with experience and expertise to confirm your problem and do the reman. replacement if, heaven forbid, that's what is required. Always sorry to hear of someone having the very annoying tranny failure. My pal who recently had to replace his in his 2004 E60 sedan was bouncing off the walls ......

Thanks for the link!

I was informed by the transmission shop that the problem was mechanical.

So I have opted to replace with a used transmission at the first shop. I am eager to get it fixed, sold and move on.

I just hope their diagnosis is correct (as weird as that sounds), don't want it to turn out that it was transmission cooling, computer, wheel speed sensor etc. and never even know about it.

Modern BMW transmissions ,ZF and GM,will not work properly with just a regular fluid.Imminent damage may not ensue,but they will not work as supposed to.And after that it takes crazy amounts original fluid to take out the other fluid out of the system.I and the people I work with always use Pentosin ATF2 and ATF3,as recommended, with great results.

I used pensoil multi atf in our 2002 x5. 4.4 until 170k miles when we traded it in. this fuild is compatible with the zf spec fluid

Ok,that is old 5 speed transmission and as much as "other" fluids are not recommended they will work fine.New generation 6 speed transmissions are different animal,but hey, this is still a free country and everyone is free to put whatever fluid he wants in his $6000+ transmission.I would not ;)

zf specs call for lifeguard 6 fluid. bmw's spec is Shell 1375.4.

you can find a number of readily available fluid that fits the spec.

redline d6 is about half the cost

my point is you dont need to pay dealer prices for fluid with BMW label

Pentosin is not in the dealer's price range,butit fits the bill perfect.
For 6 and 8 speed transmissions BMW specified fluid is ATF2 and/or 3.Again,I dont know for a successful attempt a different oil to be used.I am cheap on tires and other stuff,but would never put anything different or unproven in my transmission or engine.$50 or 100 saved every 2-4 years could lead to so much doom I dont even want to think about.
In that spirit,many firends are laughning at me because I run $12/qt Motul Le Mans 20W60 oil in my race car,and change intervals are hardly over 600-700 miles.But once my oil pump failed I did more than a mile at full tilt before I figured out something is wrong.The engine was not even knocking on idle and all i had to do was to replace the rod bearings.

ZF lifeguard 6 is NOT a "BMW product" nor does it come with a "BMW label". Only an idiot would buy it from BMW.

$20 a liter. Yes thats a lot for motor oil every 7500 mils. Not for 7-12 liters of ATF every 50k miles

Given how rarely one changes ATF and the ~$70-120 difference in price, why run fluid that isnt spec'd by ZF?

Perfectly fine to experiment, but readers should understand that they are in fact experimenting.

BMW's spec for fluid is Shell 1375.4

if I use a fluid that fits this spec. how is this wrong? unproven?