Freelander 2 XS TD4 Rattle on acceleration

Hi Guys, a mystery noise coming from somewhere under my Freelander. Its a knocking rattle that sounds like a tin sheet hitting something rotating. Not always there, but cornering can start it off, then it is there during acceleration, particularly up hill, and sometimes stops when cruising. I've crawled under and tugged on anything that might move; nothing found. There is a recording of it here: https://youtu.be/pTzpgHYvGEg Any suggestions very welcome - I haven't got much hair left.

Have a look at the solid metal pipe at the back of the engine running from the turbo to the intercooler (IIRC). There isa bracket welded onto it to clamp it to the engine. Mine broke and developed a rattle just as you describe. Took pipeoff and got a local company to weld it back on (better that the original I might add)

The saga so far. Not having a pit, I couldn't examine the back of the engine, so gritted my teeth and took it to a local garage. Told them the symptoms and the possibility of the pipe from the turbo. The had it for a couple of days, took it for drives and believed the sound was from the rear. Uncoupled and recoupled the electrical connection to the haldex unit, and the sound went away! Despite spending (they said) about three hours on it, they only charged me for one, with the suggestion that we drive it for a couple of hundred miles and either bring it back if the noise reoccurs, or at that point have a service on the haldex. Well, within a day the bloody noise is back! So, before I visit the garage again, I've been trying to understand how the haldex unit could be making that sort of noise. It just sounds a bit too tinny and there are no error messages about drive train showing up on the dashboard. Any suggestions please.

Is the noise proportional to engine speed or vehicle speed?

Make yerself some HippoRamps

Well, It has eventually been sorted, and it was the Haldex unit (located at the back end of the prop-shaft, contains an electrically operated hydraulic clutch to distribute power to the rear wheels). On first visit to the garage, it refused to perform, so after suggesting it might be the Haldex, they gave it back to us with instructions to return it when it made a noise again. Of course it did the next day (and the frequency of the rattle was proportionate to the speed of the vehicle). I needed some convincing as to how the Haldex could be producing that tinny clunking sound, so did some homework. I came across this great video by haldexrepairs.co.uk explaining the Haldex: youtu.be/K4xDvn-EMWQ but I still wasn't convinced how the tinny sound was produced. However in the absence of any other explanation, I handed it back to the garage for a Haldex service.
On collecting it, I was shown photos of the large amount of steel swarf in the unit's congealed oil. Apparently looking at the Haldex is not part of regular servicing, so this hadn't been touched in 58,000 miles. They had removed the unit, cleaned and washed it, and replaced seals and filter. The noise went!!! I guess the tinny quality of the noise was transmitted by the hollow prop-shaft.

Here's what it cost, by an established independent garage, August 2024, ex VAT:
Parts:
Sealing ring £12.73
Oil filter £58.26
Differential oil £31.70
Total: £134.39
Labour: £206.25
Grand total + VAT: £408.77