Gearbox whine in 1st, 2nd and 3rd

No clunks and goes into gears ok but whines terribly in 1st, 2nd and 3rd. 4th is absolutely fine. I am suspecting worn bearings as the oil is clean and full. Anyone else got this or is this a common problem? I knbow replacing the box would sort it but it seems a big (and expensive) job. Any advice gratefully recieved.

Also, what do you use for an interior light as mine doen't have one and I can't see a dam thing in the dark apart from the dash light.

theres probably a few worn parts but lay shaft bearings are your whine

Is that a recon box then? Is it a big job to change (I'm new to Landrovers!)

gear box out and bellhousing off at least ,though youd probably be best rebuilding the box whilst its out