Transmission keeps going into safe mode

Special tool from BMW works through the transmission oil pan, you can't buy the tool so BMW dealer is the only place to go.

BMW has been using electronically controlled automatic transmissions in most models since the late '80s. These transmission systems employ a transmission control unit which controls electrical solenoids to manipulate the various control and shift valves and functions in the transmission valve-body. When the transmission control unit detects a problem that it "thinks" could be damaging to the transmission or engine, it goes into a fail-safe or "limp" mode. In this mode, the transmission will function in reverse normally, but in forward it will operate in only one gear (whether you have the shifter in D, or any of the lower gears). This will typically be 3rd or 4th gear, depending on the model. It will start in this gear and stay in this gear with no shifting. You would experience this as sluggish acceleration and higher than normal engine speed at about 40-mph and above.
If you must drive the vehicle when the transmission is in the fail-safe mode, accelerate gently and keep the road speed lower than full highway speed.
Earlier models do not employ fault codes and must be diagnosed manually. Late models do employ fault codes and a diagnostic/scan machine can be used to check and read the faults to assist in diagnostics. Note that this is not your common OBD-II engine management fault code tool. This is what A BMW dealer or a properly equipped independent shop would have for full vehicle system diagnostics and coding operations.

Safe mode the car will go in forward, 2nd gear. If it's not going forward, you waited to long. Time for a rebuild.

1. if automatic, try to shift gear to drive then back to park then try to start again. do it twice , if still wont start
2. check battery terminals if lose or with white substance pour clean water until substance is dissolve. then start.
3. check battery
4.

IMO it's more likely that you have the wrong grade of ATF. It's very important to have the correct grade. The following site shows this:
http://www.nairaland.com/1364064/automatic-gearbox-problems
each car manufacturer has recommended grades of Automatic Transmission Fluid, BMW is no exception. the following website for BMWs may bring you more accurate data:
http://www.nairaland.com/1364064/automatic-gearbox-problems
Apparently CTSC is the supplier for BMWs via the web.
Generally auto gearboxes have drain plugs and filler plugs to enable oil change in routine maintenance. But I would definately go back to the garage where you had the last service and ask politely about the grade of ATF used, before considering an 'oil change'.
Good Luck

Sounds like your transmission is bad. You'll need to take it to a shop to have it checked out.

That cog lite IS the transmission service light.

Change the fluid and filter. Don't do it yourself or have the monkeys at Jiffy Lube do it. They'll screw it up.

I may have a similar issue, it's hard to tell from your description. My transmission is in 'limp' mode with a fault light on the dashboard. It basically causes the transmission to lock into third gear. Acceleration is poor because you are starting out in third gear. I'll let you know if I sort it out. It could be the switch on the brake pedal. Others have had luck switching that out

quoted from BMWE34.network
" Transmission locks in "limp" mode - 3rd gear so you can "limp" home or to your nearest dealer."

"Things to check before even contemplating a transmission overhaul:
Check electrics - Alternator and battery.
Replace DME Relay and Fuel Pump Relay - not expensive.
Remove disassemble, clean and reassemble gear selector switch - If it looks beyond saving, replace ($200)
Service the transmission ($130 from a specialist) and check/replace transmission speed sensor ($90)"

With any manual transmission you shouldnt just go from 6th to 4th bc it is bad for the transmission, if i am in 5th gear and i want to go into 3rd i always go from 5th to 4th to 3rd as a preventative maintenance. If you have a defected transmission you should be able to get it warranted by the bmw dealership you bought if from though.