We have heard some reports of Ranger and BT-50 (they're the same vehicle mechanically) suffering oil pump failures with fairly terminal results for the rest of the engine. The other quirk with this engine is that you can't drain the engine of oil and leave it for any more than a few minutes without the pump running dry and needing to be primed before the engine is started.

Not all mechanics know this and many a Ranger or BT-50 engine has been destroyed when the oil has been dropped from the sump and the mechanic has gone to make a cup of tea or do some paperwork. They return half an hour later, replace the sump plug, fill the engine with oil and start it up. But because the pump hasn't primed, there's effectively no oil pressure and the engine is reduced to scrap in a few short seconds.

The problem is partly to do with the different design of the pump and there are even companies that have engineered more conventional oil pumps to replace the standard units on these engines.

If this is a new phenomenon, then it’s almost certainly down to the condition of your tyres. As tyres wear, they become less able to clear the water between themselves and the road surface, allowing the car to almost 'float' over the bitumen, leading to the loss of traction you’re experiencing. But even a tyre that is simply old (as opposed to worn out) can cause the same problem as the rubber hardens and loses its ability to grip the road. This will also be most noticeable in wet conditions, which is when you’ve experienced it.

Another possibility is that the car has sprung an oil or coolant leak which is spraying from the engine bay, under the car and on to the rear tyres, causing them to slip. But that’s a lot more of a long shot and a close inspection of the tyres would be the first step to curing what is a potentially very dangerous situation.

This is, indeed, a known problem with Ford (and other) automatic transmissions. The layout of your transmission uses the engine’s coolant to cool the transmission by running a transmission fluid line through the radiator. And yes, when that line fails, the coolant mixes with the transmission fluid. That leads the transmission to fail mechanically (the coolant doesn’t lubricate the transmission) as well as the coolant destroying the transmission’s computer.

By insurance, I take it that you took out an extended mechanical insurance policy when you bought the car, because general car insurance won’t cover mechanical failures such as this. Given the get-out clauses with which some of these policies are riddled, I’m not surprised that you aren’t covered for the full cost of the repair.

Mazda increased its factory warranty to five years/unlimited kilometres in August 2018, but when your car was new, it was covered for only three years. I’d still be giving my Mazda dealer a call, though, as you might find the relatively low kilometres you’ve covered might convince them to make a pro-rata offer for part of the repair costs. I wouldn’t hold my breath, but it’s got to be worth a try. And, no, I don’t consider 98,000km to be a reasonable distance for a modern transmission to fail.