The previous owners had tried for about 3 years to solve the torque bind problem... various mechanics had suggested and done various things, but the ATF hadn't been changed for almost 100K km (60K miles). I guess it never occurred to them that the ATF might be the problem, cuz they sold it to me thinking that it needed CV joints. After I checked the CV joints and found nothing apparently wrong I figured changing the ATF was worth a try, and it sure did make a huge difference. Hopefully the problem that you mention about the Duty-C solenoid won't be an issue, although it seems the car had been run for quite a while with the torque-bind problem and dirty ATF. Other than that, it seems the car was regularly serviced and repaired.
I just drained and refilled, adding Lubegard... and plan to do it again in a couple of weeks. Thanks for the confirmation that this is a common issue with the 4EAT transaxles.