This could be caused by a range of things, but it’s also worth noting that this model was subject to a recall back in 2017 for a problem very, very similar to the one you’re experiencing. The recall involved Rangers built between June 5 2015 to February 12, 2016, so a check of the build date on your vehicle is the first step. A Ford dealer will also be able to tell from the VIN number whether the car was affected by the recall and if it’s been fixed as a result.

The problem involved a retaining clip that held the gear-shift cables. In some Rangers, this clip or clamp was not tightened sufficiently, and could allow the cables to make contact with the vehicle’s driveshaft. Over time, this contact could damage the gear-shift cables as well as the actual driveshaft. Difficulty in changing gears was one of the tell-tale symptoms.

Beyond that possibility, you need to check the shifter mechanism (including the cables) and maybe even dig into the transmission itself if nothing is wrong externally.

There are many things you should look out for before buying a second-hand workhorse like an XL 4x2 ute. Most never have an easy life.

Are there signs of abuse and/or neglect? How was the tray/load bed used, was it a tow vehicle and what does the type of wear and tear does it have?  Was the vehicle off the road at any time, and why? This may indicate a major accident.

Finding answers requires a level of trust and taking the vendor's word at face value, but you can back these up with service records and history. Are they complete, and carried out by a Ford dealer or specific Ford specialist? If the answer to either is no, then that should be a red flag. In our opinion, these vehicles require specialised Ford maintenance.

Furthermore, having 15,000km service intervals is a bit of a stretch for such hard-working vehicles, so skipped ones is especially worrying.

We also recommend taking the Ranger to an independent mechanic for inspection, especially to check the body and suspension underneath for signs of over-loading or off-roading. 

Since the PX generation was launched in 2011 Ford has issued many recalls for the Ranger, and some are serious, including for being a fire hazard over tall grass due to exposed exhaust. The car's service history will indicate whether all recalls have been carried. You can crosscheck them at this website: https://www.productsafety.gov.au/recalls 

Rangers are known to have issues with the automatic transmission, engine control module (ECM) failures (that send the truck into 'limp home mode' in hotter climates or after long-distance driving), air-conditioning, turbos and engine crank bearing. Most of these should be picked up by an experienced mechanical check-up before buying, or sorted out under warranty if you decide on a newer model.

This sort of advice applies to all used trucks. Fundamentally, the T6 Ranger is a solid, safe, durable, comfortable and enjoyable truck to own and drive, and remains the only one (along with the T6-based Mazda BT-50 from 2012 to mid-2020) that is designed, developed and engineered for Australian conditions, so don't be put off.

Just make sure it has history, ask pointed questions about how it's been used and don't be afraid to insist on a mechanic's report.

We hope this helps. Good luck.

Call back and ask what was done to ensure nothing else was affected. I would want them to tear the gearbox down, flush everything out, and check the internals before putting it back together and installing the new torque convertor.