Re:That super short grinding noise in first gear...

I agree with fordem and others as the origin of the noise probably being the transfer case. I had a 3rd gen for 6 years and about 200k km, manual gearbox, and it used to have a transfer case whine - back then it worried me more so I took it to the dealership and I was told it is normal. Now I have a 4th gen for about 3 years/60k km, automatic gearbox, and I have the same noise, perhaps a bit reduced. Just to be sure, when I noticed it a few months after purchasing the 4th gen I reported it to the dealership during a regular maintenance visit and I was told once again it was normal.

The noise I am talking about is a whine which is more noticeable - as some folks have mentioned - when taking off, specially on steep hills. It subsides to a background humming on highway driving for me. Not concerned about it anymore, but I have been thinking about soundproofing the cabin floor in order to make it quieter. I recently changed the transfer case oil and there was no evidence on the drained oil of any sort of issue. I agree that bigger, heavier tyres/wheels requiring more torque to be transfered through the drivetrain could result in a louder whine. I swapped the original HT 195/80 tyres for AT 215/75 ones with clearly more rolling resistance.

Regarding the different approaches to this noise that Suzuki branches have, it probably goes according to local regulations. Here in Brazil I read an article in 2020 stating that there are no laws for limiting cabin noise.

Earlier this year I put a single layer of Kilmat under the carpet of my wife's JB74, it made a huge difference to the gear noise but did not eliminate it, I'm considering a second layer, time will tell.

I don't think the whine is the transfer case, and that's because the automatic JB74 that I drove didn't do it - I've driven one automatic and two manuals, both manuals whine and the auto didn't suggesting that the whine is the manual transmission - even though the whine is road speed dependent and not affected by gear selection.

When I fitted a transfer guard to mine it made the "singing" from the transfer box really noticeable- I think the flat plate was reflecting sound upwards into the cabin.

A piece of that closed cell sound insulation stuck on the inside of the guard has quietened it down considerably.