Mitsubishi L200 rough/rumbling noise at 1500rpm when accelerating, particularly loud in 6th

Can you hear it at 1500 rpm when vehicle stationary or only when driving ? Check all hoses , turbo hoses , air filter , air intake .

Thanks for your response.
It is only occurring when driving from 1500rpm to around 1700rpm. Noise not present when stationary.

When you get a noise that you cant replicate when stationary and can drive through it at 15/1700 rpm it's hard to pinpoint . No exhaust heatshields or mountings loose , tap cat convertor and silencer boxes for any loose baffles etc ?

I’ve had a couple of hours this morning under the bonnet and car. Nothing at all loose. Nothing, as far as I can tell is leaking either.

I’m beginning to think it’s in the gearbox/transmission area, possibly....???
3-4 gear synchro is on its way out, could the sound be linked?

I’ve booked it in for next Monday at my local garage.
Hopefully they take a look and run some tests and get to the bottom of it, if I can’t beforehand. ????

Obviously if you decide to do 3/4 synchro it means a box strip down and you can then check layshaft bearings and other bearings at same time . Hopefully check on Monday turns up something minor .

Problem solved!!
Incase anyone incurs the same noise in the future....

Whilst having my 3/4 gear synchro changed. (2 month wait for the parts!)
It was noticed that the gearbox mounting was snapped, 2 of the 4 lugs had sheared, New mount fitted when gearbox reinstalled,
She runs like a dream now.

Gearbox ‘Donut’ bearing and U joints all still pristine, which were my ‘guesses’, should we say... I’m no mechanic. But had them checked over to eliminate them.

Sidenote and off topic: I Was shown the old parts from the 3/4 synchro change too, they looked bloody brand new still! The selector had no wear or fatigue, nor did any of the other parts, all the teeth on the gears still. Was shocked. They looked like brand new parts!
But she now stays in gear and sounds like new.

Happy driving folks!