auto box problem

ive just bought a 1995 discovery 300tdi auto,apparently the transfer box and rear diff were replaced in janruary.the problem is that when pulling away selecting drive does nothing,the only way to pull away is select 1 until moving and at around ten to fifteen mph u can put into drive and the box works fine through the gears.again when slowing down u have to select 1 again!!!
can anyone shed some light as to possible faults?
many thanks paul.

today whilst fiddling with the high/low gear lever (which was very stiff)it moved and now while driving keeps jumping out of high into neutral........losing all drive!if i keep gentle pressure on the lever it stays in high!
please can anyone give me a few ideas where to start!!!!!!!!!!

Post in the right area.

You'll just get ignored otherwise.

Autobox problem is a clutch pack failure.

Hi/Lo is probably because the linkages are semi-seized. Need cleaning and lubricating.