Vibration high speed with drivetrain engaged

So I've noticed that my Hiace vibrates like crazy at high speeds, although mostly with drivetrain engaged.   This starts to get aggressive around 90kpm and gets worse at you get faster.   If you depress the clutch, the vibration gets much better, which suggests to me that it's drivetrain related?   I ran into another post about this and someone recommend a vibration sensor on the phone to help diagnose it.   So here we go... I got an app for the iPhone called VibrationAnalyzer and drove with a couple of different conditions (1) 5th gear, gas down going 100kpm around 2500 rpm (2) 100 kpm in neutral (clutch depressed) and (3) 5th gear, gas down going 90 kpm (maybe 2200 rpm?)

These photos can be found:





One of the other threads suggested that at that rpm, gear, that a drivetrain vibration might work out to be 40 Hz and anything in the wheels would work about to be about 10 Hz.    Honestly it seem like the major peak was a little higher than this but this is the data that I got.  

My question, should I just buy 4 spider U-bolts an replace them then be on my merry way.   Is there anything else that the data is suggestive ?

Hi - no idea, sorry, But I was wondering how the vibration is if you put the clutch in (or put it in neutral) and then bring the revs up to 2500? Both while going along and stationary?

Had something similar but not with the Hiace.
Had to fit a new UV joint bearing on the prop shaft.
It took away the vibration.

Hello peiell.

Great work to log the information. Very thorough and organised.

There are all sorts of thing this could be but my plan would next be to work out the rotational speed of the various parts. I think these are mainly 1, engine speed, 2, gearbox output speed, which is also prop shaft, 3, half shaft, which is also wheel speed.

The blocklayer site: https://www.blocklayer.com/rpm-gear.aspx might be ideal for inputting the gearing, diff ratio etc to work out what’s turning / rotating / vibrating at what speed.

If I’ve got my sums correct then 50Hz is 3000rpm (50 x 60) so that’s maybe your engine speed?

You’ve another quite wide band somewhere  about 17Hz, which would be ~1000rpm.

You’ve also got a third bump somewhere about 2Hz, which would be ~120rpm.

I don’t know vibrates at those frequencies at those speeds but the blocklayer site might tell you. Once you know the category you just need to narrow it down. This might be need some further examination.

HTH!!

Late update to this one, but like probably many of you suspected, the U-joints on the front drive shaft were completely shot and the vibration was much much better after replacing them. Bad news, my rig completely blew up again and I'm at a big loss of what to do. I've had the rig for nearly 5 months, and driven like 300 km on it. Ack.

That sucks. What's happened?