when the tc has an internal fault, it just disables itself and the front no longer gets any power.

When I did the post mortem autopsy on the TC I replaced it looked perfectly ok with regards to the gears etc, so I'm not sure what died but I think it was the clutch wear surfaces.

The oil was black and the burnt smell was terrible: made the garage stink for a couple weeks.

Researching before I replaced the TC, and found a few examples of the internal fault, none that recovered.

I didn't see any way for the rear to disengage which doesn't align with BMW's claim of 100% power to either axle, maybe that's for newer models.

I had to drive the one I repaired 75 miles not knowing if the bull gear was 90% through the teeth and about to just split apart and join me in the cabin.

It appeared to me that I could have driven 1000s of miles

After replacing the TC and cleared codes all back to normal and the lurch at 1500 rpm disappeared.

The RED brake apparently is the TC is blown signal. Oddly it also represents the opposite side of the spectrum= e brake engaged or also low brake fluid.

BMW techs have said can also be the control module. Drain a little fluid onto a white paper towel and see if it's smelly and dark, if so sadly I think the TC is toast.

I found a used one for $500 with shipping and 6mo warranty. I charged my client flat rate of $300 to install. Add the $50 or so for fluid and another $10 for replacement bolts for the exhaust and $860 is not bad considering the alternatives.

Pull your actuator motor and apply 12v fwd and reverse or run a test mode if you scan solution provides it.

When I pulled the actuator and had it hanging down by the power cable and ran the test mode with foxwell nt510, it ran fine and that's when I was sure the thing was blown

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)