Let's play 'name my vibration'.

So, with full throttle acceleration in 1st (maybe 2nd) i get this wicked shudder in the 530iT&A. You can actually hear it too. Varies w/ speed. Floor it on the highway and ya just don’t notice it though.
Rev her hard in neutral; nothing.
Center support/bearing, tranny mount?


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93 SE-R---94 530iT&A---92 325i ….”Hang up & Drive!”
”It is not the function of our government to keep the citizen from falling into error;
It is the function of the citizen to keep the government from falling into error."--Robert H. Jackson.

the easy things to rule out are the center support bearing, flex disk, tranny mounts, diff mounts... If those check out ok, then it may be the driveshaft. While you have the center link exposed, grip each side of the driveshaft (on either side of the U-joint) and twist. If there is any play, even 1/16th inch, the DS needs replacing. It could also need rebalancing.

i had this 2 months ago, it's your center bearing, i bet if you get down there, you'll notice that the rubber is not even there anymore. Also it most likely will eat up your flex guibo if you dont get to it soon. I let mine go for a while like this and it chewed mine up.

yep I also vote for center support bearing

Before you pull the centre bearing, check the condition of your rear tyres. When I first got my 535, the last owner had put a cheaper low profile tyre on the car, (silverstone or something) and given it some hard driving. The tyres had the flat spots on the inside edge that you couldn't see from the outside. When I removed the tyre and got under the car to check for worn bearings, bushes etc I left the tyre standing verticle in the garage. As I climbed out from under the car you could see the deformations in the rubber like a nobby dirt bike tyre. New tyres, problem solved.

Highway cruising at speed is very smooth ever since.
Just a thought. Cheap to check first.

John 535is 1989