heres a half solution to the common clonk you get when taking up drive on older R380 type gearboxes
the clonk occurs because of wear in the splines on the output shaft of the main gearbox and the input gear on the transfer box
you can cure half this wear by replacing the input gear for a modified cross drilled type which allows the oil flow onto the splines
simply remove the power take off cover on the rear of the transfer box, tap out the rear bearing holder ring ( theres a recess on the main casing to allow this) remove the input gear and fit the new one
though you will need the bearing to go on the gear first
i bought my new gear and bearings from beamends cost about £70
this can all be done while the gearboxes are in situe
ta jon