A new transfer box from Vauxhall will set you back around £3000 fitted and even a reconditioned one will cost nearly a grand.
Even if its gubbed, he still got a good deal!! & the car will run ok on FWD...infact alot of owners opt for a locked box when theres go!!!
If its 4x4 you are meant to rotate the wheels regularly....this helps preserve the life of the nasty transfer box