While driving at about 65 mph, my differential seized up causing complete lack of control. Spun a few times ending up on shoulder of highway. Happened around 11:30 at night. If it had happened during daytime traffic the
result would likely have been catastrophic.

Does anyone know if this happens frequently?
The shop my car was towed to said they had three other instances of the same thing happening with this model.

 

WOW. it's a very dangerous. Call to Toyota let them know.
Did you have oil serviced right for transfer case, I meant level?

 

Boy!!!
This is scary.....Did the "diff" give you any warning? Like maybe noise or a surging as you were driving that would indicate that there was perhaps a seriously chipped tooth on one of the gears or that the gears were not meshing correctly?
I'm with the previous responder, Was there the proper level and amount of lube in the differential?

 

It vibrated about a second before failure. I thought I was getting a flat. Then all hell broke loose.
Called Lexus national, being diagnosed now.
Will let you know.

 

Good thing that no one was injured.

Was it the front diff or the rear?
Did you had any work done recently prior to the incident?

 

How many miles are on this car? You should also file a safety defect report with the National Highway Traffic Safety Administration. Link below:

http://www-odi.nhtsa.dot.gov/ivoq/