you might want to look at this thread and have the electronic clutch checked - (28) AWD drive system - any details? | Toyota Nation Forum

 

Thanks for that tip; a family member suggested this as well. Time to investigate is in short supply; will keep you posted as to what I can accomplish in my garage.

 

Mystery of the frozen rear wheels resolved! (sort of...} You might remember the adage, "Take a hammer to it!" Long story short, that's what I did. After seeing no warning lights, disconnecting the battery, checking fuses, I resigned my self to a major mechanical deconstruction, starting with pulling the rear brake rotors off. Taking my hard rubber/plastic hammer, I struck the rotor a number blows to jar it loose. Lo and behold, I noticed movement! Sure enough, the hub would turn. Repeat the procedure on the other rear rotor, and voila, both hubs were rotating again! Replaced the wheels, took it for a spin, and all was well; no scrapings or grindings, or noise of any kind. Source of the problem? Dunno, and didn't care to do a major investigation at this point. My sense is that moisture and possibly some dirt, and sitting idle for a few days must have caused some metal surfaces to bind. Where, I don't know. So, if someone has further insights on the workings of the rear hub and brake assemblies, or has a desire to find out, I'd love to hear about it.

 

Parking brakes seized inside the rotor hats due to rust jacking?

 

Possibly? I noticed that when I applied the park brake, the rotors locked tight. When the park brake was released, there was slight rotor movement .I could hear a clicking when I moved the rotor back and forth.

 

Not unheard of for parking brakes to seize whether from rust and/or hardware coming apart in the rotor hat. Though it's more typical in winter, especially after slush or a car wash, then freezing overnight.

I've seen someone driving down the street with a rear wheel locked up, screeching, skidding, bouncing... quite a sight/sound to behold.

For peace of mind, I would take the rear rotors off and inspect the parking brake hardware. Wouldn't want things jamming up while driving.

 

When was the last time you flushed the brake lines? On the 2.7 L I4 FWD the rear passenger-side brake caliper nipple will bleed the whole system. I use a bake bleeder bottle with hose that pushes onto the bleeder nipple, and I can then pump the brake pedal to push fresh brake fluid through the system. Initially, I use a turkey baster to suck out all the old fluid from the reservoir under the hood, fill with fresh, and then flush system.

My 2.0T Passat would actually bleed the calipers automatically, and dump the old oil into the reservoir. You could see it build up over time, just needed to suck out the old oil before it got recirculated. The antilock brakes get pretty hot and cook the oil. If the oil does not get flushed out regularly, maybe cooked oil could make the brakes stick?