Pajero II 3.5 LWB - high speed vibration

[DakarBandit]

Good day forum,

I have a very annoying issue with my 1999 Pajero 3500 GLS (LWB) Blister fender and I hope someone can help me solve this as I'm currently just throwing thousands of rands at the problem and it's still there.

Backstory:
I purchased this beast of a vehicle through a private sale in late 2019 as a project for weekends / long trips with the family. Its a fantastic specimen with very low mileage (190k) and seems to have mostly been well cared for over it's life.

The problem:
*High speed vibration that is present between 85km/h and 120km/h
* Deep vibration that starts as a rumble and progresses to a vibration around 100km/h
* Seems to improve upon acceleration
* Seems to get worse on deceleration (foot off the accelerator)
* Rumble returns after 120km/h
* Up to around 80km/h it rides like a new car

What I've done so far:
* Reconditioned the props and unis (slight improvement)
* Replaced/balanced out-of-round tyres (no improvement)
* All wheels have been balanced at 3 different shops to rule out incompetence (no improvement)
* Replaced worn transmission mountings (slight improvement)
* Replaced shocks all-round (no improvement)
*[Unrelated] I have also refurbished the entire front suspension and steering parts

I'm at my wits end and it's costing a fortune to just replace parts without knowing whether it will solve the problem. I have trawled through countless forum posts with similar issues and everything I tried so far was suggested as a solution, sadly this approach is very costly with no guarantees... Has anyone else experienced these issues and able to give me some advise / point me in the right direction?

Thanks for reading.

[GreenMachine]

Hi, unfortunately I have not experienced something of this nature.

But I can suggest that you try get someone to check if your front and maybe even rear brake discs (although the rear discs shouldn't cause something like this) might be warped? It shouldn't be too expensive to have someone look at it for you.

I see you mentioned that you did balancing at three different shops, did you try wheel alignment?

Please keep us posted.

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[GreenMachine]

Also, have you checked the condition of you engine and gearbox mounts?

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[DakarBandit]

Hi, unfortunately I have not experienced something of this nature.

But I can suggest that you try get someone to check if your front and maybe even rear brake discs (although the rear discs shouldn't cause something like this) might be warped? It shouldn't be too expensive to have someone look at it for you.

I see you mentioned that you did balancing at three different shops, did you try wheel alignment?

Please keep us posted.

Sent from my SM-G930F using Tapatalk

Thanks for the reply and Apologies for the slow response, I don't receive notifications for some reason.

I have had the brakes checked, the rears are ever so slightly warped but not enough for this. Since my last post, I actually replaced the tyres and the problem is still there. I have also replaced the gearbox mounts and it made a slight improvement in that there is a narrow band between 120 and 130 now where the vibration is slightly less, but still there. Upon inspection, the mechanic advised that the engine mounts seem to be fine and were possibly replaced at some point.

Someone else has advised to check the prop center bearing which makes sense - but the shop that reconditioned the prop said it was fine so thats questionable now.

I guess a second opinion couldn't hurt..

[jacodv1]

I had a Prado with about the same problem. To cut a long story very short..... The prop shaft to the front was not balanced correctly. I had it balanced 2 times at one place and when a second shop took it they did a good job and months of frustration ended !