2002 Renault Laguna 6-speed

I own a 2002 renault laguna 1.9 dci 6 speed It has covered only 76,000 miles. It has recently developed problems in 1st gear.

As you put in 1st gear and engage the clutch, the gearstick moves about an inch towards the neutral position. As you move on past 1,000 revs, a whining noise occurs that at its peak sounds similar to a sticking cambelt.

Anyone with any ideas - is it likely to be a transmission rebuild or maybe a drive shaft problem?

The problems occur only in 1st gear.

Thanks