bad vibration...

[FS5]

my car's devolped a real bad vibration.i'm asuming its the tailshaft ,the faster you go the worse it gets,it starts vibrating around 105kph and gets very bad when i go faster.you can feel it vibrating up through the gear stick.it dosen't matter what gear its in ,it will do it in 3rd,4th,and 5th as long as i'm doing 105kph or better. .
i put some new front rotors on last weekend and thought maybe they had something to do with it.
i scrubbed the bottom of my car out on a steep driveway last week to,maybe it hit on the tailshaft and bumped it a bit and put it out of balance or something ?or bent it ???i didn't think it scrubbed out bad enough to hurt anything though.
if it is the tailshaft,is there any advantage of getting an alloy one from the wreckers and getting it balanced and putting it in?or should i just get the standard steelone re ballanced?

[Jokular]

This might sound dumb but could it be your tyres?
Check pressure etc.. $40.00 wheel alignment?
My car was doing a similar thing after wheel alignment and pressure it was heaps better.
It's still not perfect cause I have directional tyres on the back and non on the front.
You probably already did these things but it doesn't hurt to mention them.
Is it making any noises from the rear?

[Casper]

check your shocks too.. the vibration could be the wheels "bouncing". had the same thing in my old EF wagon and it turned out to be shocks. Strangely it used to happen at 115kph exactly.. everytime... every gear.

[Eu-GenixX]

i also recommend checking the tyres....

my ex had a mirage.. used to vibrate like crazy on the freeway.. and used to make a flapping type sound specially when turning left

turned out to be a huge egg in the no name tyre on the back... changed the tyre.. and it was all good...

check for the flapping sound....

[blacklabel]

Originally Posted by Jokular

This might sound dumb but could it be your tyres?
Check pressure etc.. $40.00 wheel alignment?
My car was doing a similar thing after wheel alignment and pressure it was heaps better.
It's still not perfect cause I have directional tyres on the back and non on the front.
You probably already did these things but it doesn't hurt to mention them.
Is it making any noises from the rear?

Doesn't sound dumb at all Jokular, I had the same sort of bad vibrations in my old maxima-at around 100kms hour,you would swear the whole back end of the car was about to fall off!
It turned out to be my rear tyres-not the condition-just out of balance, and the bad vibrations were going through the whole sub frame and chassis.
Would be the first thing I'd check.

[FS5]

thanks for your input guy's,i've had a chance this arvo to have a good look at it.

theres no scrapes or dings on the tail shaft,and the unijoints are fine.so i'm assuming the tailshaft is fine.
the gearbox mount bolts are done up tight,i couldn't check the bolt that goes through the centre of the mount to the gearbox.i don't have a socket thats goes over it.
all suspension and tramp rods are done up fine.i gave the shocks the old bounce test and are good..
i checked the tyres and they seem fine ,no eggs or iregularitys
could it be a broken engine mount???
last time i was out at the drags i noticed it had a bit of a vibration in it on my last run going across the finish line.
the vibration is definately coming from the drive train somewhere.i can rev the car out to the limiter in 1st and 2nd with no strange vibrations or sounds.the problem is also speed related the faster i go the worse it gets.
any more suggestions are more than welcome.

[FS5]

i got the tyres balanced yesterday,its made it a bit better .the rears were out 15 grams each tyre.
the car still dose it though.i took it for a drive on the motorway yesterday trying to feel where the vibration is coming from.there is definatley no vibration coming thruogh the steering wheel.it feels like its coming from the diff?????
i also noticed that when i push the clutch in the vibration goes away used:
could it be something with the clutch????
like said in the previous post,i can rev the car out in 1st and 2nd and it feels great no vibration at all.
its got me frazzled!!!

[Stav]

Does it pull to left or right at all?

[FS5]

no mate,it drives in a straight line.
one thing i have forgot to mention is that the car has been hit up the rear twice in its life time.but it has always driven great after the repairs though.

[Eu-GenixX]

if it goes away when the cluth is in.. i'd assume it's not driveline...
if it doesn't do it in 1st and 2nd... i'd assume it's not the engine...

if it's speed related and not driveline or engine.. that leaves tyres/suspension...

can you borrow a set of wheels off someone to take it for a run on the highway?
or swap the wheel front to back.. see if that makes a difference... perhaps your wheels on another car and see if they get a vibration too....

[FS5]

i jacked the car up and had another look this mornin ,i got a long ring spanner and put it between the gearbox and the cradle that the mount bolts to.i could easily lift the gearbox an inch and it didn't take hardly much force to lift it.is this to much movement??
the bolt that goes through the mount is done up tight.to look at the mount dosen't appear to be crack or broken.

[Stav]

Id put a stand under the box for support and then remove the mount to check it properly.

[mr302xd]

my au is doin the death wobbles at about 120 feels like the cars gunna fall apart!!

[FS5]

i just put a new gearbox mount on it and it is still doing it.
the vibration definately goes away when i push the clutch in.

[xr8ute]

Have you had a real good look at your engine mounts?

I had a bad vibration in the ute that I couldn't put my finger on. I thought I found it when I checked the gearbox mount (could move it a good inch with little effort)...it improved but after only a couple of weeks it was back as bad as ever.

I didn't find it until I pulled the engine out, the studs on top of both engine mounts had sheared off. The engine must have been moving around like crazy, tearing up the gearbox mount in the process I suppose.

I thought I had checked my engine mounts well enough, but obviously I hadn't.

Unbolt the mounts and lift the engine a little from underneath with a jack (to take the weight off the mounts), so you can check them properly.

[FS5]

thanks mate,i'l jack it up again and check the engine mounts properly
one thing i did notice ,that under hard excelleration the gearstick will lean to the right .quite a bit actualy a good 20mm +

[FS5]

i took it to mate's today thats a mechanic ,and he put it up on the hoist .we checked everything.the engine mount are fine unijoints are fine .
what we did fine thats the rear bush's are are a bit worn but not to bad.while he was checking the tailshaft and unijoints ,he found that there was some play in the diff.its hard to explain but i'l give it a go.the bit that the tail shaft bolts to at the diff ,you could actualy move up and down ,not much about a poofteenth.so we dropped the tail shaft and undone the bolt thats in the middle and he had a bit of a look ,cleaned the nut up ,put it back together and done it up tight.its taken the movement out of it now and you can't move it up and down know more.
i haven't had a chance to give it a run along the freeway yet to see if its fixed the problem,i'l go up the freeway to work tomorrow and see how it goes.
i was putting ,getting the diff rebuilt off as a long as i could .but now i might get it done to be on the safe side.

[Blighty1979]

My AU XR8 (200kw) ute is doing a similar thing. Under acceleration at 110 to 120 km/h it will vibrate in third forth and fifth. I drove a mates ute which is almost the same (185kw) is doing the same thing although a little less noticeable. I have had the tailshaft balanced and the unis changed.

[FS5]

mine was the thrust bearing .
is yours a manual?
i had a series 1 xr8 that did it too.it was a manual as well ????