ok, so i started the drive home today for a decent 3 hour trip, and all was good, car drove as smooth as anything!

i came to a bunch of cars that were bunched up too tight to overtake easily so i overtook the whole lot, my speedo is out by 10ks but i think i may have reached the 160 170 mark before i even looked at my speedo, in which case i hit the brakes and pulled in...

now it vibrates alot at around 60ks and continues up through to around 120, although when the clutch is out and the car is under slight load it is almost gone, its when the clutch is in it vibrates the most, and it vibrates when i brake also which i assume was the rotors warped when i hit the brakes at a high speed...

i checked the balancers on the rims, and checked all the tires themselves, it has new front bearings, joints, shockers and whiteline swaybar, but i haven't touched the rear end?

could this be the tailshaft, rear bearings, diff (which does not seem to be lsd, even though i was under the impression that all XGs were) or rear housing on the gearbox? (t5 manual, new clutch)

any help would be great, need to know i'm not going blow up for no reason on the way to work tomorrow lol

Tailshaft might need a balance and rear union join might be busted.

My Brother (SpeedyED) has had this problem before, it turned out to be the bolts connecting the tailshaft to the Diff had worked themselves loose, all he did was clean the threads on the bolts up, purchase brand new bolts, and loctited them in with 243 Sealant.

Do you know if your tailshaft is Steel or Alloy? if you've been hitting things like speed humps at great speed then that will most definitely bend the tailshaft. If it's Alloy it will be more prone to getting bent because of the material is softer.

Other than that the only thing that could make a tailshaft go wacko is like what Phong has said and the Uni Joint's have pretty much just had it, Uni Joints should have ZERO play in them.

EDIT: Correction, he purchased brand new NUTS, not Bolts.

Question, when the car vibrates under braking, is it the whole car that vibrates? or does the vibration go through the steering?

The general rule of thumb for that one is that if the steering wheel vibrates under braking it's the front rotor's that are warped, if the whole car vibrates while under braking it's the rear rotor's that are warped.

Ok, is it hard to check the uni? Just looking for play?
Will it cost much to balance the shaft?

I'm positive it's the front rotors as I've done them plenty of times on my DF, they aren't bad tho, the least of my worries

Steering box has very little play also

another general rule of thumb would be to not advertise the fact that it occurred on a public road...

also if your speedo is out 10km/h @ 100km/h i believe it will be out around 20km/h @ 200km/h possibly reading 180 or thereabouts.



Hate to sound like a killjoy but couple that with someone else in the line of cars your over-taking that has the same idea as you but doesn't check mirrors = you not being able to do much about ploughin up their date or going bush at "170km/h" not that I know the circumstances...

i reckon dc_todd would have a good pic for this thread...

Yea, no worries mate, thankfully it was all good

I got under the car today and found that all the tailshaft bolts were loose, that's the source of the vibration, but they were tight before I left...

I will tighten them up and make sure they're the ultimate source of the vibration and haven't just come loose from another source, if they're it, I'll invest in some nylon nuts

Should use thread locker on tailshaft bolts...I personally wouldn't use nylon nuts. Loctite blue (medium strength) should do the trick...I wouldn't go anymore than medium strength, because it will be a pain in the a*** to remove with anything stronger.

i put 290 super wick in on mine after i done them up last conversion and haven't had a problem yet... if it's vibrating that bad to shake bolts loose maybe it's shaken the weights off ?
another option if the bolt is long enough is use a locknut. Nylocs are ok but technically they're only single use & some bolts aren't long enough to engage the nylon at full torque.