Please help; what is happening to my trans??!
 

'97 Outback, 2.5L/Automatic trans with 108K on the clock.
Just recently, the "AT Oil Temp" light started flashing intermittently on startup. For the last two days, it does it every time. In conjunction, it seems like the car doesn't want to back up with the wheel cranked...and it has started clunking when I shift into park. I think the clunk is coming from the rear. Also, just the way things feel, but I get the sensation of the rear is locking up when I take a low-speed turn--it's like the car seems to throw out an anchor. Can anyone tell me what is going on with the car? Thanks in advance!

have you changed the A/T oil? the filter? check those 2 out first!!!

Yes, they were changed at around 65,000 or 70,000 miles.
I'm not sure if the rear diff oil has ever been changed...does it need to be?

Okay, here's the deal. There isn't a lot of information anywhere about this, but this is what happened to me:
It was the solenoid valve in the transfer case (on the end of the trans) that engages and disengages the rear wheels to drive. This is a common issue. Solenoids are only good for a few million pops and then they die. In my case, whenever power was applied (car to start), the solenoid would pop open and engage the rear wheels. You could even feel it happen. $530 later for about 30qts of trans fluid (these transmissions need to be flushed several times for it to be worth it), 3 hours of labor (part of that to mildly resurface the engagement hub on the trans side--as opposed to rear side), and one new solenoid valve ($180 for that by itself), and the car is running like new again. I had the work performed by a local trans shop that has experience fixing Subaru transmissions.
I spoke to the guy who performed the work, and although he isn't quite sure how to diagnose it (aside from removing power from the solenoid to see if there's a mechanical connection--bad, BTW), he knew how to fix it. Furthermore, he only knew slightly more about diagnosing it than I did. He just knew how to fix it. On a side note, he said that sometimes, the engagement hub (kinda like a flywheel) gets edges on it that make it hard for the solenoid to pull the clutches back. Sometimes that can be the problem. He said that he'd never replaced one and wasn't sure if it could be done without completely replacing the trans.