Odd vibration around 80km/h

**stocky** · 03-03-2009, 02:40 PM

Posted this up before, but still havent worked out the problem. Driving my car between 60-90km/h i notice a very annoying pulsing vibration. It seems to happen every second. Probably 0.8 seconds to be close to exact, and seems to increase a little in frequency/harshness as the speed gets higher. Once i hit 100km/h, its not as noticable. It is very annoying though. Every time it vibrates it shakes every loose thing in the car and gets very irritating. Could it be wheel weights, tailshaft unbalanced, or something else?

**greenfoam** · 03-03-2009, 02:43 PM

Ask Morton

he's fixed his

**stocky** · 03-03-2009, 02:45 PM

was his a similar issue to this?

**ephect** · 03-03-2009, 02:57 PM

im thinking torque converter.. try this, when the vibration is pressent, drop the gearstick from D to 3rd without changing the throttle position and see if the vibration disappears

other than that if its still pressent, could be centre bearing, possibly wheelweights or tailshaft

**greenfoam** · 03-03-2009, 02:58 PM

Yeah he had weird vibrations, I think he had a broken engine mount, maybe the gearbox mount too

**stocky** · 03-03-2009, 02:58 PM

i should also mention its manual

**greenfoam** · 03-03-2009, 02:58 PM

Originally Posted by ephect

im thinking torque converter.. try this, when the vibration is pressent, drop the gearstick from D to 3rd without changing the throttle position and see if the vibration disappears

other than that if its still pressent, could be centre bearing, possibly wheelweights or tailshaft

It's a manual

**ephect** · 03-03-2009, 03:05 PM

lol sorry guys, stocky i should have known better! im guessing it does it in all gears..

Foams i think ur right bout the mounts, either engine or gearbox

**stocky** · 03-03-2009, 03:11 PM

well the engine mounts were replaced about 6 months ago just after i bought the car, so possibly the gearbox mount? anyway for me to go out and check it?

**ephect** · 03-03-2009, 03:27 PM

i'll check my manual tonight if noone posts up info before hand.

**vcstarfirequeen** · 03-03-2009, 03:29 PM

sounds like a wobble in the bottom end

**ephect** · 03-03-2009, 04:41 PM

ok, below is the proceedure for check and renewal as per Haynes

1. Raise the vehicle and place it securely on jackstands
2. place a lever or large screwdriver between the crossmember and the transmission and try to prise the transmission up and down. if the mount is cracked or torn, renew it.
3. unbolt the mount from the crossmember and from the transmission.
4. support the transmision with a floor jack and raise the transmission until the mount stud is clear of the crossmember, then remove the mount.
5. refitting is the reverse of removal.

will check the front for any more details on vibrations

**Chirpstr** · 03-03-2009, 05:05 PM

Exhaust fouling on something can cause issues like that.

**CommodoreMan** · 03-03-2009, 06:03 PM

Sounds like you need a wheel balance explains why you can only feel the vibration at certain speeds, same thing happened with my car at 90Km.

**BlackVXGTS** · 03-03-2009, 08:52 PM

Balance your rear wheels.

**ephect** · 03-03-2009, 09:06 PM

Q: is the vibration relative to the rpm or speed?

if its rpm orientated regardless of gear, always round say 2000rpm, its not drivetrain related
if its speed orientated, its drivetrain related

**stocky** · 03-03-2009, 09:07 PM

i dont think its gear related. seemed to be the same if i was in 4th or 5th at 80km/h, and i think with the clutch in too.

**ephect** · 03-03-2009, 09:55 PM

i would be getting wheels balanced first, start simple.

other possible causes

bent or dented drive shaft
worn uni joint bearings
loose drive shaft mounting nuts/bolts
or worn transmission rear bush

JD · 03-03-2009, 10:18 PM

buckled wheel possibly?

**stocky** · 03-03-2009, 10:20 PM

nah its not a buckled wheel. theyre all fine

**dijm8** · 03-03-2009, 10:23 PM

i reckon ur tailshaft rubbers hav gone, check them

**stocky** · 18-03-2009, 02:09 PM

had a look at the transmission mount. it seems fine. thinking i might swap wheels over with the VN to test it for a balancing issue. what tailshaft rubbers do i check?

**greenfoam** · 18-03-2009, 02:46 PM

Seems fine? or is fine

? there's a big difference, you can't tell unless you've pulled it out and wriggled it

**stocky** · 18-03-2009, 02:54 PM

i tried the screwdriver method above. didnt seem to want to move the box much at all

**Not_An_Abba_Fan** · 18-03-2009, 03:26 PM

Check your centre bearing on the tail shaft.

Is it a grumbling sound coming from just behind you about level with the back of the console?

If it wasn't for the vibration I would have said front wheel bearings, but because it vibrates as well it sounds like a tail shaft issue.

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