sudder in 5th on the highway...

[jonson]

i have been putting up with this annoying prob for ages, but seeing as i have the brains trust here i am fairly sure you guys could tell me whats goin on...

at highway speeds, 80kmh+ at cruise, or off throtle, there is a big vibration which feels like its from the drive line (not through the steering, or audable in the cabin even) i have been told by some one it could be a diff mount ? its a live axle, manual V6.

cheers guys

JT

[tully2007]

Is it only in 5th or at that speed?
Only things I can think of is bent or out of balance tail shaft, wear in the universal joints or in the front joint sleeve in the extension housing.
Check all the rubber bushes of wear.

[jonson]

i dont think its just in 5th, its more at highway speeds, but i will double check.

i will check all the bushes for wear, coz i dont know what im looking for whe it comes to the universal joints or in the front joint sleeve in the extension housing

cheers

[tully2007]

To check the universal joints you have get under the car and with one hand hold the shaft coming out of the diff and with other manipulate the tail shaft up and down and around, there should be no play in the joint.
Do the same at the other end. To check the tail shaft, get the back wheels off the ground, and make sure the axle is on stands not just a jack and chock the front wheels, then place a pointer as close as possible to the centre of the shaft and slowly turn the wheels by hand and see if the shaft touches the pointer.
It may be a lot of mucking around but it might find the problem.

[tully2007]

Do you have steel wheels? Maybe one's buckled. Just a thought

[jonson]

sweet cheers, i'll have a go at all that over the weekend.

and nah, not steelys, holden mags

[STEALTHY™]

80k's is abit low for 5th (i know its the fuel saving gear, but T5s don't like low load on the box)

Did you work out if it does it in 4th at the same speed?

[tully2007]

Anything that rotates has a "critical point" no matter how well balanced it is where it will vibrate, so anything turns should be suspect. Even the tyres!

[JA2Z]

First thing i would suspect is the wheel alignment or uneven wear of the tyres or Brake Discs.

If you can get a tyre joint to align all your wheels and check if you have any uneven wear on your tyres. should be under $50

Also check or have someone check your Discs, if you have uneven wear on them they can cause shuddering at higher speeds.

Cheers

[curtiscreative]

Is your car lowered? It is possible for your tailshaft bolts to come loose.