CX-5 auto gearbox issue??

[bencx5]

Afternoon all, I am in need of some advice please, we had our CX-5 recovered home to Somerset from York over the weekend (took the RAC 26 hours - was a nightmare) as its developed a problem and i didn't want to risk further damage. I'm trying to work out the best place to get it fixed so the question is whether it is likely to be a gearbox problem or not.

We bought the car in December 2016 2.2D 175 sport nav auto AWD with 32,000 on the clock and FSH. (now done 37,500m)

Ever since we've owned it the transmission has been quite whiny, especially around 40mph, but according to my local Mazda retailer that is relatively normal for a CX-5 auto so I didn't worry about it. This weekend gone we drove some 250 miles to York which is the longest trip we've yet done. On arrival in York there were new noises coming from the front, they sounded to me like a wheel bearing, but the car had only been MOT'd the week before so that seemed odd. The noises were most noticeable at low speed, particularly when allowing the car to coast to a stop while in Drive, say approaching a junction and getting ready to stop. Applying the brakes at low speed also made the noise worse.

A local mechanic put the car on his ramp on Sunday morning and found the following:

Nothing amiss in terms of brakes or suspension that he could see would cause a noise.
The bottom of the gearbox was too hot to touch, we had only driven 10 miles to see him but it was a scorching hot day.
The transfer box was slightly lacking in oil but not critically in his opinion, we replaced and topped up anyway.
When rotating the front wheels in opposite directions - little or no noise.
When rotating the front wheels in the same direction - much clunking
We didn't drop the ATF as he had none the right spec to replace, but we assume it is full as we have no signs of any leakage whatsoever.

The gearbox behaves beautifully, silky smooth, never had a problem with it.

So, has anyone got any ideas or been through similar?
Is it normal for the gearbox to get that hot after such a short journey?
My father in law has suggested it could be the output shaft bearing?

Any advice would be gratefully received so I can take it to either a gearbox specialist if required and get it back on the road as we miss it!

Thanks in advance, Ben

[McTrucky]

Sorry, I am a bit late to the party, but wondering how this played out?  Is it resolved?
I am not (yet) familiar with the layout on the CX5 but I expect the following:

Turning both wheels the same way would I assume cause the prop shaft to turn; and turning them opposite ways would just be spinning the front differential.
The noise happening when the prop shaft is being turned does point to the transfer box, which hosts the bearing your father in law suspects.  If the noise can be identified as definitely coming from the front, this is where I would be investigating - and the fact it was low on oil may be a smoking gun. 

If you can't isolate to the front, then the rear diff needs to be considered - how does the AWD work on these cars?  Is there a Haldex system (set of wet clutches open/closed by oil pressure from an electric pump activated by the ECU), or is it some other mechanism?