The Mitsubishi Pajero Owners Club®

[Jilvia]

HI,
I recently got a 2001 Pajero 3.2 did diesel.
I have a noise that is driving me crazy and I don't understand the nature of it. When I switch from first to second, especially uphill, it makes a sort of "thud thud", non-metallic at the rear, like a light knock.
It doesn't do it when stationary when I engage first gear, not in reverse, nor in other gears.. Before I try and spend thousands to change every single screw, can you help me think and understand where it comes from?
Ps I have already replaced the 4 differential supports

[Google]

[iam_TJ]

You don't say if it is manual or automatic transmission or short or long wheel-base.

If it is manual transmission then generally changing up gears, especially first to second, causes a distinct loss of forward inertia. Consider also that at the lower speeds when doing that change there is relatively low wind-pressure on the body chassis and parts.

I wonder if what is happening is that some component is "hanging" slightly loose such that when the gear change occurs and inertia is briefly lost and then regained the component swings forward and then back, causing the double thud sound. At higher speeds wind pressure possibly pushes this hypothetical component back and holds it there whilst lower ratio (higher gear) changes don't cause the same degree of loss of inertia. When adding in mention of hills it is possible this causes the component to hang in a 'better' position to induce the double-thud.

As to what it is ... something in or around the fuel tank possibly? If long wheel-base and with a rear air-conditioning unit fitted under the rear-right corner maybe it is loose? How about something in the fold-away seat recess in the rear cargo floor such as the jack?

What about the suspension struts and/or coil springs and their mounts and buffers?