Unfortunately you are merely adding to the stats of owners suffering failure of this CVT gearbox.

I wonder if the gearbox fluid and filters have ever been changed?

It doesn't matter whether the car was mis- described either.....no one can predict the future.....it can be fine one moment and fail the next.. there is no warranty.....he is still stuffed.

Edited by Colin Pomeroy on 23/04/2022 at 16:31

The £5400 is presumably based on a new gearbox and main dealer labour rates, I’d be on to eBay for a used box, and a competent independent garage to fit it.

If the OP does this and the gearbox is a munter he will still have to pay for the garage to fit it and then pay them to remove it, it will not be their problem if its rubbish.

If he goes for a used replacement it should be from a recommended specialist who give some form of worthwhile warranty.

If that is not possible he would be better selling to car on e-bay as it is for someone else to sort.

Not so sure this is a good idea to get a secondhand box for these models as I was the workshop foreman in a Nissan Dealer and sadly the failures on these are very common and there a lot of failed ones out there.

Nissan do an exchange box which is cheaper than a new one. or see if a local auto gearbox specialist can repair or try John Mackey in Glasgow www.mackie-transmission.com as they do repairs on Nissan Gearboxes.

Good Luck.