4x4,
Starting in '01, the 4wd system became ATRAC (4-wheel traction control)...no locker is available. ATRAC first came on the Land Cruiser in '00.
Besides the 4wd system, the braking system also changed in 2001:
1. ABS is now with Brake Assist and Electronic Brakeforce Distribution (EBD).
2. ABS is now 4-channel, 4-sensor, instead of 3-channel, 4-sensor. This is needed because of the incorporation of ATRAC (4-wheel traction control system) and VSC (stability control).
In addition, something that you found out already, the transfer case is easier to operate!
The other differences are probably minor. I have a 6-disc in-dash CD changer/radio combo...do you have it?
Other than that, i don't know. Try reading the archives on the 2000 model and 2002 model...they may mention the changes.
Sorry, can't help you more.