I have a 2004, Borg Warner which also stuck in 4L. Yes it's a common problem, & from what I've read it's been one for sometime.
This one is newer than most of the posts and threads I've found, after taking it apart to look at it I found the problem in the position sensor, contained in the very outer gray cover where the wires go in. It's obviously one of those "no user serviceable parts inside" gadgets but being as it was screwed up anyway I pried it open to have a look.
One of the contact brushes was bent & mangled, which I was able to straighten it out and got it to work once with the motor assembly out and laying on the ground. I took it apart again and found the contact mangled again, from a rough spot on the sensor disc I imagine. But at least now it shifts from 2W to 4H.
I found another motor on E-Bay, which started at 25.00 and wound up at 43.00. Till then I'll carry a 10MM socket and a T15 Torx in case I get in a bind and really need 4L. The case can be shifted with the motor off fairly easily - a pair of pliers will get you going again in a pinch once you get the motor assembly off, - about 5 or ten minutes worth if the plug doesn't give you too much trouble. Mine comes off without removing the dampner also, so four bolts and the plug basically.
I've heard of guys driving around with the motor assembly off and shifting as they need to manually. Also I found a bolt on gadget called a Shiftster I might try if I have more trouble down the road.