voyager 2.5 turbo diesel manual box probs sticky into 1st & 2nd
 

just bought this 5 speed manual 3rd gen turbo diesel 1998 , it wont go into 1st gear while moving & 2nd is stiff. all other gears are perfect .it has to be absolutely stationary before it will go into 1st . all other gears are fine no crunching etc . i thought maybe clutch ,but i actually stopped the engine while on the move ,tried to engage 1st at about 10 mph ,and it still wont go in .which would seem to discount clutch drag !
funnily enough it will go into 1st while coasting in reverse (obvioulsy did'nt lift the clutch :) maybe bad oil in box ,does anyone know the correct grade ?
any ideas appreciated .
thanks for looking