[maslin]

I’m honestly trying to be helpful. Our cars do not have electric parking brakes. With the car off, the abs is off. Reverse, neutral or drive will all be neutral with the engine off.

If the car won’t move with the key off, parking brake off, trans in anything but park, something is mechanically seized. Pulling fuses, checking codes, etc is pointless.

Every rear diff I’ve seen seize went just like you said. Driving along, starts to drag, barely make it off the road, then it’s just locked. I’ve seen it a lot of times, on various chassis. It’s a differential, there’s nothing special about it being in a frs/brz.

Every one I’ve seen lock up was due to lack of lubrication. Either a hole popped in the housing by something on the road, or a leaking cover that leaked long enough to run completely dry.

Wheel bearings tend to come apart, not seize. Same with carrier bearings. Automatic transmissions tend to lose park, not break in park. Also wouldn’t go the way you described, the parking pawl can only drop in at a low speed, wouldn’t slow you down at speed, just make that fun click click click bang noise. If the trans or driveshaft was stuck the wheels would still turn in opposite directions.

The only thing that can really stick and totally lock both rear wheels is the diff. Usually a pinion bearing gets really hot then seizes when you stop. If the gears come apart you get nasty crunch noises, or it stop suddenly at full speed.