My J reg Fourtrak TDI has ben fine, but recently when switching back to 2WD and driving off, there is a banging from the wheels, and the sort of groaning/grinding too. It seems not to have fully switched back to 2WD. When I reverse a few metres, and drive off again, the fourtrak is back in normal 2wd and no banging...

Should this be checked out, because I dont mind reversing a metre or to to get back into normal 2WD mode if I have to. Don't want to spend any money if pos unless it will be badly damaged if I dont do somethings now....