There is a procedure to bleed the 4wd system. From memory on a 32gtr it goes something like,
1. fill the reservoir to about 3 cm over the max.
2. remove the air from the bleed valve on the unit above the rear diff.
3. turn the ignition on
4. disconnect the bleed connector which is behind the kick panel near the accellerator pedal. It should be a white or yellow wire with an inline connector that you need to disconnect. You should hear the pump start for a couple of seconds.
5. there is a bleed valve on the back of the gearbox/transfer case, you need to unscrew it nearly all the way, then open and close it quickly for 1 sec at a time. You should hear the pump pulse then close then value. Do this until all the air has gone.
6. there is pipe (the return) on the side of the reservoir on the tail light side (the reservoir is on the right hand side in a r32). Open this to drain the excess fluid by connecting and disconnecting the bleed connector near the accellerator pedal. The pump should turn on when you connect the bleed connector if not turn the ignition off and off then try again.
7. connect the bleed connecter and turn off the ignition.
Sorry for the confusing explaination, it is easier with pictures although the engrish in the manuals is probably worse.
Unfortunately this didn't help my friend, his problem is abs or electrical related.