auto gearbox fault

hi everyone, wonder if anyone has came across this fault before ?
when i select drive there is none at all , however if you select 1st gear and pull away you can then select drive and box will change up and down gears all day . until you stop then you have to select 1st again to move off again
any ideas anyone ?
its a 2000 my 4.0

regards jim

Sprag clutch failed in the box. James Martin will probably be along to confirm, he knows a lot more about the auto box than I do.

one way clutch ,sprag clutch same thing yes i agree

thanks, for your reply's datatek & jamesmartin.
will have to have a think wether to go ahead and get another box or get this one taken out and repaired or just sell it the way it is

regards jim