I don't know what model you have, but I know a friend whos had two prados, did mention a clutch problem with one of them.
Theres a post here that does allude to that I guess and a fix for the future <no toyota genuine parts.
http://www.justanswer.com/australia-...18-months.html
I'm not sure its a great idea to take on a boat ramp (similar grade )
in your car right now ,, let alone a mountain !
good luck