You may have a collection of problems rather than just a single one. The vibration through the steering wheel could simply be the vibrations from the diesel engine travelling up the steering column and into your hands. Does the vibration go away when you rev the engine to just off idle? If so, perhaps an adjustment to the idle speed is all that is required there to move the engine out of its resonant patch.

A vibration in the cabin could be a worn wheel bearing, out-of-balance driveline, a worn torque converter, broken or worn engine mount, broken exhaust mount, damaged tyre, a wheel out of balance and plenty more. But the play in the front driveshaft coupling would be a smart place to start looking. Again, the problem comes and goes because of the harmonic periods inherent in things that spin very quickly. Any out of balance problems can easily show up as transient vibrations inside the car.

No, there was only one automatic gearbox, a six-speed unit that was vastly more popular than the other choice, a six-speed manual. For the 2017 model year, Holden upgraded the automatic transmission with what’s called a centrifugal pendulum absorber torque converter.

This absorber was a type of dampener designed to reduce vibrations form within the torque converter and improve the driveline’s smoothness. But this was applied to all 2017 Colorado diesels, meaning the transmission differs from a 2016 or earlier unit.

Since both variants of Colorado here use essentially the same engine, I’m not sure what sensors would be different and require changing. That said, the MY17 Colorado got recalibrated hill-descent and hill-start functions, so maybe there are some differences there.

The major mechanical difference that I can see between a 2014 and a 2017 Colorado is probably the power-steering. In late 2016, the vehicle switched to an electrically-assisted system in place of the previous hydraulic set-up. So the later engine would probably lack the pulleys and mounting hardware for the hydraulic power-steering pump that your vehicle requires. Perhaps they can be removed from the old engine and fitted to the later one.

Perhaps an easier solution would be to return the engine originally supplied and ask for the correct version for your car. If the engine supplied originally was not fit for purpose, then you’ve every right to ask for a replacement unit that is.