Driveline Vibration Fixed - 302 / TKX / IRS / Early 2024 MK4

[Waterman]

My new MK4 has only been street legal for a few weeks and I am slowly attending to a few issues and dislikes. One was a vibration in the seat of my pants. It was actually to the point where my eyes would not always focus due to the vibration. Probably a combo of some engine vibration but also definitely some driveline vibration. I believe the driveline is now quiet so I thought good to document that since I do not see much on the forum on this with the IRS. I had read the tranny and diff should be parallel so initially tried that with a large spacer under transmission. See attached how I came up with 1" shim as the best. My old 1979 T-bird 302 is running a bit rough so still a little vibration at certain speeds but goes away as soon as clutch goes in now, initially not. Engine being replaced this winter! With the Kirkey Racing seats you feel all the bumps.
I would be interested to hear from other IRS builders what shim size they used. Tks
Fixed an error and made easier to read for future ref. See PDF not pic.
216377

[gbranham]

It's my opinion that folks get hyperfocused on driveline angles needlessly. I didn't measure mine. I eyeballed it, and none of my angles looked severe with 3 of Forte's spacers. Mine drives great. They're u-joints for a reason; they can tolerate not being perfectly aligned. In fact, they operate better if they're not perfectly aligned.

Greg

[rich grsc]

!00% correct, stop trying to make "PERFECT" driveshaft angles. They are designed with U-JOINTS so they run with angles. With IRS nothing moves, install it and move on.