Td5 Gear change trouble.

Im beginning to think Ive got a lemon. Last weekend I had a problem with my brakes so my disco td5 hasnt moved for a week. I replaced a pipe and hose yesterday, went to fire it up and the battery was flat. So this morning I recharged the battery and decided to take it on a trip up the dual carriageway and back. However it feels like the gearbox is full of sand. Doesnt like changing gear, especially shifting down. It wasnt a problem last time I drove it. Any suggestions. Ive had about enough of the thing atm.

Ok. I got back in to check the gears change without the engine on. Everything seems ok. Took it down the road and everythings back to normal. Im so confused.

Check oil level

Do you mean gearbox oil?

he does , when was it last changed as well ,its best changed regularly