Firstly some technical info.
2012 Dual Cab SR, ~170k kms
265/65/r17 w/ basically brand new Maxxis bravos
As far as I'm aware, its still running on factory suspension / brakes etc.
I'll give you a bit of a back story to my problem. As the title suggests, the ute is shaking at around 100kph. It's been doing this since I bought it in November of last year. I've replaced the factory steelies along with the goodyear wranglers that were on them with black steel rims and the maxxis's. Initially the shaking was coming through the steering wheel (textbook wheel balancing issue) , which the new wheels and tyres seemed to fix for a while, however in recent months the shaking has come back and its worse than before. This time however the shaking doesnt seem to be effecting the steering wheel like it did before, and seems to be coming more through the floor / rear of the car. At 100kph the front passenger seat is wobbling like crazy. I've had the wheels balanced, rotated and aligned twice by 2 different tyre shops / mechanics. I've also had the suspension looked over and was given the thumbs up on that as well. It has been recently serviced, with the uni joints on the drive shaft greased and everything checks out in the eyes of the mechanic.
Another thing to mention is that the vibration / wobble isn't consistent. Sometimes it rides perfectly smoothly for a few seconds depending on the steering input, angle of the road and incline etc. Putting the car in neutral and taking my foot off the throttle seems to have no effect on the shaking either.
I am currently in the process of getting new rotors for the front as they're no longer round (steering wheel shakes when braking) but not sure if that would have anything to do with the issue that I'm dealing with.
I've spent hours going over this forum and several others, and it seems to be a common occurence with the N70's shaking at 100kph with balanced wheels.
Sorry for the paragraphs but I've tried to be specific as possible and provide as much info as possible to hopefully narrow it down, or find someone thats had similar issues.
Any help would be greatly appreciated. Getting very tired of being slowly shaken to death every time I take it on the highway.