No Power going to the wheels

Hi.
Hoping someone can give me a heads up as what the problem is with my 2003 MCS R53 - 142000miles.

I put in for a CV Joint (Front Left) - garage could not get the CV joint off so ended up removing the drive shaft and replacing complete unit with CV Joint.

About a week later I went to pull away in 1st gear at a roundabout when the car started moving forward then nothing - no power to the wheels. Engine running normally and I can select any gear but no drive going to the wheels. Is this Driveshaft related or something different?

Garage have not had time to look at it properly but they say there is a drip of oil coming from the gearbox so they suspect something in there has given up. I al concerned it will cost an arm and a leg to drop the gearbox and get in there to fix whatever has failed and with the car being 2003 / 142000miles its just not economically viable.

I am hoping its not terminal as I have spent a heap on the car with Ohlins Road and Track coilovers, GTT Tuning kit - reduced puilley - Airtec intercooler, sports exhaust etc. Theres no rust and the car did drive like a dream - very quick.

If anybody can give me a heads up as to what might be wrong with it I'd appreciate that.

Thanks folks

Is there any noises coming from the gearbox?

More than likely splines on drive shaft gone

No noise from gearbox. I can select gears as normal. However nothing happens when I lift foot off clutch.

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Thanks. So would that mean I just need a new driveshafts fitted? The garage just replaced the drive shaft but could it be defective?

Either the driveshaft splines are damaged or the gearbox end is damaged most likely rounded off and because no LSD no drive although you would expect to hear some noise