I have a 2016 Nissan X-Trail and wondering what causes a transmission to need replacing?

A: Transmissions are a wearing part of any car, In the case of the X-Trail, the vehicle used a CVT transmission rather than a conventional automatic. The CVT uses variable pulleys and a steel belt to vary the gearing and allow the engine to accelerate the car efficiently. In decades past, the CVT was not as durable as other types of transmission, although recent advances have made it a more robust unit

The specific servicing required by a specific vehicle varies from model to model, and there’s also a recent trend towards transmissions that don’t – according to the manufacturer – require much maintenance at all, including regular changes of the transmission fluid. Old school mechanics don’t always agree with this sealed-for-life strategy on the basis that clean fluid never harmed a transmission, while worn out or contaminated fluid certainly can. Heat is the natural enemy of transmission fluid, and if you live in a hot climate and do regular highway driving, chances are the transmission has been pretty hot at times.

In any case, the experts reckon that 100,000km is the maximum distance you should drive between fluid changes in your Nissan with its CVT. Was this done during your ownership or according to the service records? Nissan’s own servicing notes on this car indicate that the CVT fluid only needs to be checked every 15,000km (and then only for leaks and level) but not replaced. There’s a clause that says if the vehicle is used for towing or in harsh conditions, the fluid should be checked for condition at 90,000km and replaced if necessary.

Either way, you’re way beyond the factory warranty period. Brand-new, your car would have had a three-year/100,000km warranty (Nissan extended the warranty to five years in 2019) so you’re well beyond both those limits.