Vibration At 100km/h

[silman]

This exact problem has occured to me this week. I have an rb25det in a 180sx, and have just had my os giken clutch removed to have the plates re-made (dead clutch). Clutch was re-made by local clutch shop, and put back in by the workshop. When the car reaches approximately 90km/h there is a humming sound, and vibration coming from the tailshaft area, seems to be coming from just before the diff area.

The vibration is not noticeable in first or second gear, only in 3/4/5th gear, above 90km/h.

If i put the car in neutral in 3/4/5th gear, the vibration/humming sound is still there.

The mechanic states he placed an indicator chalk mark on the tailshaft upon removal, and re-installed it at the same spot, as from previous experience if the tailshaft is not placed back at the exact position, then vibrations can occur.

I've never removed the tailshaft personally before, but I can see that it has 6 allen key bolts that bolt to the joiner for the diff. In the centre of those 6 bolts, I assume there is a spline? I was thinking the spline may be a tooth or two out, but i can't see how this is possible, if there are 6 bolts lined up in place? Is there a spline in there? Here's an old pic of my tailshaft/diff;

Edited April 30, 2008 by silman

[silman]

ok, just got back from the shop. Found out that the spline is just on the gearbox side. The 6 allen key bolts on the diff side of the tailshaft were done up by another employee of the shop, and that guy had done up the bolts, 1 at a time clockwise.

Another employee loosened all of the bolts, then re-seated the tailshaft, and then tightened the bolts up in a star pattern. I took it for a drive, and the majority of the vibration is now gone. There's still perhaps a 5/10% vibration there, as opposed to say 30% previously. To people who have vibration problems after a clutch install, try this as a fix. Make sure the mechanic marks the tailshaft position mark before removing it.

Edited May 2, 2008 by silman

[opp61]

ok, just got back from the shop. Found out that the spline is just on the gearbox side. The 6 allen key bolts on the diff side of the tailshaft were done up by another employee of the shop, and that guy had done up the bolts, 1 at a time clockwise.

Another employee loosened all of the bolts, then re-seated the tailshaft, and then tightened the bolts up in a star pattern. I took it for a drive, and the majority of the vibration is now gone. There's still perhaps a 5/10% vibration there, as opposed to say 30% previously. To people who have vibration problems after a clutch install, try this as a fix. Make sure the mechanic marks the tailshaft position mark before removing it.

Buds,

My goodness. I have the exact same problem with my series 2 GTS. Got the car 4 weeks back and have been pissed just trying to fix the problem. Car vibrates at 110 all the way to speed cut at 180 km. Same on power, off power and in neutral and even with clutched depressed. Changed rims, tyres, balance etc. Same crap.

Got the prop shaft removed yesterday and doing a balance now. Centre bearings all look ok. Will ask the mech to tighten the nuts in a star formation and see if this helps too. Just cant stand the vibration.

Will update if this solves the problem.

Cheers

[opp61]

Buds,

My goodness. I have the exact same problem with my series 2 GTS. Got the car 4 weeks back and have been pissed just trying to fix the problem. Car vibrates at 110 all the way to speed cut at 180 km. Same on power, off power and in neutral and even with clutched depressed. Changed rims, tyres, balance etc. Same crap.

Got the prop shaft removed yesterday and doing a balance now. Centre bearings all look ok. Will ask the mech to tighten the nuts in a star formation and see if this helps too. Just cant stand the vibration.

Will update if this solves the problem.

Cheers

Update 10/5/08

Changed both drive shafts.

Installed balanced long shaft. Same problem.

Will remove and reattach the 4 lugs which go to the back LCD diff in a 180 rotation on Monday.

Last thing to do is change the gear box bearing which attaches to the long shaft.

Dont know what else to do.....

Edited May 10, 2008 by opp61

[grey pearl]

Update 10/5/08

Changed both drive shafts.

Installed balanced long shaft. Same problem.

Will remove and reattach the 4 lugs which go to the back LCD diff in a 180 rotation on Monday.

Last thing to do is change the gear box bearing which attaches to the long shaft.

Dont know what else to do.....

The thing I notice with a lot of posts about faults that occur after work has been done on a vehicle is that people fix everything unrelated to the problem trying to fix it, when what you need to ask yourself is was this problem present before the work was done,if not then it is first and foremost related to the work that was done and therefore your first port of call should be to take it back to where the work was done and tell them that it wasn't doing it when you brought it there and you want it fixed at their expense.

Also in order to make them aware of this fact you need to let them drive it ,if it is driveable,before you leave it, then there will be no argument as to whether the problem was already present when the car was dropped off.Grey Pearl.

[Rekin]

Took my car back to suspension workshop. They removed all my aftermarket bushes, regreased them, fitted and wheel alignment. (camber, castor)

Vibration seems to be gone now..very interesting haha

The vibration was present before/after I had my bushes first installed, but now the vibration is gone once they re-installed them..

So, my results;

- Vibration after clutch installed (vibration)

- New adjustable bushes installed (vibration)

- Tailshaft balanced (vibration reduced 50%)

- Adjustable bushes refit (vibration reduced 90-100%)

So balancing the tailshaft and refitting the bushes has removed the vibration.

Anyone know what the problem could have been?

[opp61]

Took my car back to suspension workshop. They removed all my aftermarket bushes, regreased them, fitted and wheel alignment. (camber, castor)

Vibration seems to be gone now..very interesting haha

The vibration was present before/after I had my bushes first installed, but now the vibration is gone once they re-installed them..

So, my results;

- Vibration after clutch installed (vibration)

- New adjustable bushes installed (vibration)

- Tailshaft balanced (vibration reduced 50%)

- Adjustable bushes refit (vibration reduced 90-100%)

So balancing the tailshaft and refitting the bushes has removed the vibration.

Anyone know what the problem could have been?

Bud

The bushes would be the last on my list of options but hey if it worked for you, i would give it a shot tomorrow.

Will update if is cures my nighmares.

Cheers

Edited May 11, 2008 by opp61

[opp61]

The thing I notice with a lot of posts about faults that occur after work has been done on a vehicle is that people fix everything unrelated to the problem trying to fix it, when what you need to ask yourself is was this problem present before the work was done,if not then it is first and foremost related to the work that was done and therefore your first port of call should be to take it back to where the work was done and tell them that it wasn't doing it when you brought it there and you want it fixed at their expense.

Also in order to make them aware of this fact you need to let them drive it ,if it is driveable,before you leave it, then there will be no argument as to whether the problem was already present when the car was dropped off.Grey Pearl.

Bud,

When I got this car 4 wks back, the vibration was already present. I brushed it off as maybe a wacked rim or bumpy tyres. They previous owner said that he hasnt done any balancing on the tyres for sometime as the car has not been driven for some time.

That was when my nightmare started.

[opp61]

Bud,

When I got this car 4 wks back, the vibration was already present. I brushed it off as maybe a wacked rim or bumpy tyres. They previous owner said that he hasnt done any balancing on the tyres for sometime as the car has not been driven for some time.

That was when my nightmare started.

Buds

Done the following today

1) Changed gbx mounting

2) Check bushes on subframe and rear suspension.

3) Changed gbox and rear diff oil

4) Confirmed that the long shaft is in sync.

5) Balanced the long shaft

AND IT STILL VIBRATES !!!!!!!!

Running out of ideas. Anybody got any more ideas?

[opp61]

Buds,

Summary of what has been done:

1) Changed both rear drive shafts

2) Change rear wheels (borrowed)

3) balanced long shaft

4) Center bearings ok.

5) Aligned cv joints

6) Vibration is on throttle, off and even with clutch in.

7) Changed gbox and diff oil

8) Changed gbox mounting

9) Checked all the suspension bushes.

Done today 15/5/08

1) New rear axel

2) Changed front wheels (borrowed)

3) Fabricated a size reduction rear piece to fit into my 4 inch Kakimotor rear muffler ( wow the car is so much more silent)

Conclusion: Still vibration at 110km+ all the way to speed cut at 180 km. When the vibration happens, there is a dull vibration which comes from the back and you can actually hear is. ( not very loud)

What else should I look at?

Wheel bearings are all ok. No funny sounds. Spin ok.

However is sound the only way to know if the wheel bearings have failed?

Really need some help on this issue.

[grey pearl]

Buds,

Summary of what has been done:

1) Changed both rear drive shafts

2) Change rear wheels (borrowed)

3) balanced long shaft

4) Center bearings ok.

5) Aligned cv joints

6) Vibration is on throttle, off and even with clutch in.

7) Changed gbox and diff oil

8) Changed gbox mounting

9) Checked all the suspension bushes.

Done today 15/5/08

1) New rear axel

2) Changed front wheels (borrowed)

3) Fabricated a size reduction rear piece to fit into my 4 inch Kakimotor rear muffler ( wow the car is so much more silent)

Conclusion: Still vibration at 110km+ all the way to speed cut at 180 km. When the vibration happens, there is a dull vibration which comes from the back and you can actually hear is. ( not very loud)

What else should I look at?

Wheel bearings are all ok. No funny sounds. Spin ok.

However is sound the only way to know if the wheel bearings have failed?

Really need some help on this issue.

I'm suss on the centre tailshaft bearing even if they said it was alright get a second opinion,I have learn't so many times that self diagnosis is the worst advice you'll ever get unless you are a good mechanic,anyway at the worst you'll have nearly re-coed the car and will reap the rewards in the future.Good luck Grey Pearl.

[opp61]

I'm suss on the centre tailshaft bearing even if they said it was alright get a second opinion,I have learn't so many times that self diagnosis is the worst advice you'll ever get unless you are a good mechanic,anyway at the worst you'll have nearly re-coed the car and will reap the rewards in the future.Good luck Grey Pearl.

Bud

The whole of last week the car was at the mechanics place. Some parts purchase and some borrowed. i.e. rear axel, wheels etc

Changed the rear bearing today and still the same problem.

I have given up on finding the root cause of the problem. My mechanice has also give up. He can't charge me for the 1 week of work as the vibration is still there. That poor bugger is only charging me for the gbox oil and long shaft balance. I will buy him some beer for his help.

Will drive the car like normal and pretend that there is no vibration at all .

I have given up.

TKO by the Skyline GTS on me !!!