KF2 4wd gearbox/transfer box trouble

[TX3]

I'm having a bit of trouble here people.Anyone got any advice about this particular prob.Thought I might of done a clutch the other day but it turns out it may be a touch worse.I have discovered that my kf2 4wd laser has a driveline prob.When you put it in gear it don't want to go and there is a grinding sound when you put it in reverse.Now I'm just wondering what thoughts are out there
as to what would be the prob.
cheers Rob