If the jack is tight, this type of noise can also come from the heat shielding under the car. Once my shielding was adjusted the problem went away, it has not come back.
I also had the jack noise. More information here:
JACK NOISE
My Jack has caused me noise dramas. I took it out and put it in one of the drawers. The corrugations in Australia will cause all of us problems at some point.
Below is what I sent to my dealer who sent it to INEOS
GRENADIER MODEL
2-seater AU Spec Diesel Grenadier. Right hand drive car.
INTERMITTENT RATTLE
The irritating rattle started about 6 weeks after the car was driven from the dealership, having driven over 2,000 kilometres. No work had been done on the car around this time. It sounded like something was rattling inside onto the bodywork.
The rattle was intermittent and sounded like it was coming from the passenger’s footwell (RHD vehicle). Occasionally it sounded like it may be in the battery box, but no further back. Turning my ears towards the back of the car, several times, suggested it was not from the rear of the car.
There was no way to reliably reproduce the rattle when driving, it would come and go whenever. The rattle happened more often at low speeds (50kph or slower) than high speeds (rare), sometimes it happened when the car was angling to the left under brakes.
CAUSE
The Jack in the rear of the car. It is likely to have been a cause, but not necessarily the whole cause of the rattle.
THE HOW
The Grenadier comes with a standard bottle jack. The Jack is secured in the rear with a bolt and a strap. The bolt is finger tightened. Over time bumps/corrugations/vibrations caused the Jack’s extension screw to loosen and over time it unilaterally extended itself upwards. The metal U shaped saddle sits on top of the extension screw, after a time it had extended long enough to hit the metal bodywork above the Jack. The Jack was still secured by its strap, but the bolt was slightly loose. Therefore, intermittently the U-shaped saddle hit the metal work creating a rattle. It depended on the position of the saddle and the car movement - explaining why the rattle was intermittent.
It was a two-part fix, the nut holding the Jack onto the bracket also required a ¾ turn. The Jack was not that loose, but loose enough to allow the weighty Jack to move on the bracket (I suspect the bracket was also bending slightly back and forth under the Jack’s weight), allowing the extension screw and saddle to move upwards.
I think the slightly loose Jack bolt was the cause of the extension screw moving upwards and the moving Jack’s saddle hitting the metal.
THE RATTLE WAS TRANSMITTED THROUGH THE BODYWORK
With a 2-seater the sound was transmitted down into the front passenger’s footwell and sometimes into the battery box. The rattle never sounded like it originated from the rear Jack area. The rattle may manifest differently in a 5-seater.
This made finding the cause of the rattle frustratingly hard. It took a few weeks.
SOLUTION
I screwed the extension screw backdown onto the Jack, then taped the U shape saddle to the Jack, to stop it happening again. The Jack bolt was tightened. The rattle was mostly gone after that but has come back, making me think there was two different rattles at work.
I checked the Jack bolt a week later and the bolt was already loose. I removed the Jack and placed it in my drawers.
The following labelled Jack is close enough for illustrative purposes; however, the saddle is a slight U-shape on the Grenadier’s Jack. It was that U-shape saddle intermittently rubbing against the bodywork creating the rattle and the body of Jack moving on the bracket.
