Vibration / Shuddering In The Drivetrain

[pixel8r]

Hi everyone!!

I've just come back from a dyno run at graham west and on the dyno the stagea was shuddering quite a bit - more and more as the revs increased.

I've been feeling vibrations through the accelerator pedal recently and the car's never been real smooth to drive. I've always thought my suspension was a bit stuffed (rear shocks are new, fronts are stock)...

any ideas as to what i should check - or get checked??

[eMsta]

i suspect its the clutch...my r33 has the same problem - but if it doesnt happen often, I could wait till the major service to replace it (which is what I might do)

Edit - im assuming ur stag is manual?

Edited September 2, 2006 by emsta2003

[pixel8r]

i suspect its the clutch...my r33 has the same problem - but if it doesnt happen often, I could wait till the major service to replace it (which is what I might do)

Edit - im assuming ur stag is manual?

nope, auto. tiptronic.

and its awd, just to clarify.

i'm thinking diff(s).

Would changing the ATESSA fluid possibly fix it up? i guess it would help in any case...not sure if thats done as part of compliance...

[Ska]

I doubt it, when the ATTESSA fluid gets low it just stops working But yeah I wouldnt have a clue, could be drive shaft maybe?

Does it happen under heavy acceleration, light acceleration, coasting, light braking, heavy breaking, light turn left, heavy turn left, light turn right, heavy turn right, easy on the gear changes in triptronic, hard gear changes in the triptronic, light gear changes in auto, heavy gear changes in auto.................?

Explain "feel it through the accelerator pedal"? Does it move on it's own? is the rpm steady/irratic when it happens? Does the motor seem to stutter when it happens?

[munchstagea]

Check the 4wd system, I have heard this issue occur due to worn tyres and a slight difference in rolling diameter front to rear.

If you are running different sized tyres front to rear that could also be the problem.

Don't want to change the tyres only to find out it wasn't them? Remove the front drive shaft and run it in rear wheel drive mode (only safe way to do it) there is a thread on here that explains how.

Rule out one thing at a time, I'd be starting there as it does sound like the 4wd system having a spaz out.

Cheers

Luke

[pixel8r]

I doubt it, when the ATTESSA fluid gets low it just stops working But yeah I wouldnt have a clue, could be drive shaft maybe?

Does it happen under heavy acceleration, light acceleration, coasting, light braking, heavy breaking, light turn left, heavy turn left, light turn right, heavy turn right, easy on the gear changes in triptronic, hard gear changes in the triptronic, light gear changes in auto, heavy gear changes in auto.................?

Explain "feel it through the accelerator pedal"? Does it move on it's own? is the rpm steady/irratic when it happens? Does the motor seem to stutter when it happens?

what i feel through the pedal feels like road vibrations - ie. like a grinding feel - like if there was a bolt loose underneath somewhere...that kind of thing - just when cruising along. I think my front radius rod bushes may need replacing so i'm not too concerned about that since i know what that is.

but the real shuddering was felt on the dyno today - more under heavy acceleration or at least at higher speeds.

as for the auto box - i have the valve body upgrade fitted (by mv automatics) so its a bit clunky anyway - i dont think its the gearbox.

might need to get it booked in sometime for a mechanic to have a good look.

[Ska]

Luke's idea is great, apparently takes 5 mins to unbolt the front drive shaft, why not try that?

[pixel8r]

Check the 4wd system, I have heard this issue occur due to worn tyres and a slight difference in rolling diameter front to rear.

If you are running different sized tyres front to rear that could also be the problem.

Don't want to change the tyres only to find out it wasn't them? Remove the front drive shaft and run it in rear wheel drive mode (only safe way to do it) there is a thread on here that explains how.

Rule out one thing at a time, I'd be starting there as it does sound like the 4wd system having a spaz out.

Cheers

Luke

not running different sized tires...although they may be worn differently at the front vs rear...

we did the dyno with the 4wd button on so was interesting to see the torque split show 50-50 until the revs got higher then the torque shifted mostly to the rear.

thanks for the tip - running it in rwd only mode will eliminate the 4wd system. will try that first i think.

[pixel8r]

Just had a closer look and noticed a leak under the front axle area - both sides. The left side is leaking more - two small 50c piece sized wet spots on the ground under the car since i parked it this morning. The diff fluid bottle in the back is above the MAX line so not sure if thats it.

Just something to keep an eye on methinks...

[CruiseLiner]

the attessa fluid bottle in boot is supposed to be above max when ignition is turned off, turn the ignition on and it will show the correct fluid level.

[stasis]

check your drive shafts wheter its loose on the universal joints or not. I have had experienced that shuttering while accelerating in a 4wd cos the universal joint that connectec the drive shaft to the diffs is loose. 4 bolts to tightern up

[pixel8r]

check your drive shafts wheter its loose on the universal joints or not. I have had experienced that shuttering while accelerating in a 4wd cos the universal joint that connectec the drive shaft to the diffs is loose. 4 bolts to tightern up

this sounds like it could be it. have spoken to a couple other people who suggested it could be similar stuff...

could anyone help a noob like me with photos of what bolts we're talking about here?

that'd be really great!!

[munchstagea]

this sounds like it could be it. have spoken to a couple other people who suggested it could be similar stuff...

could anyone help a noob like me with photos of what bolts we're talking about here?

that'd be really great!!

Yep, search and you will find... I don't like when people just reply with "search for it") so here is the link:

Remove front drive shaft

Search does work well though and a lot has been covered and will be covered over and over again, it is better to dig up an old topic and add to it than start a fresh one as then we end up with all the important information and solutions in one (or less places) and it will make it easier for the next newy to find the wisdom you have shared. Enjoy.

Cheers

Luke

[pixel8r]

Ok, just had a good look underneath and no loose bolts connecting the front drive shaft or anything...

I'm probably thinking of the more difficult things too soon...

Could be as simple as a good wheel alignment/balance etc.

Plus I still think my front suspension has some issues.

Not going to worry too much about it right now. thanks for the help guys.

[stasis]

ok when you are driving at what speed when the vibrations is at its worst? do you feel the vibrations on the sterring wheels or from the car seat? If its from sterring wheels its the front whels problem and if its from the seats its the rear wheels. Let us know. We have to get to the bottom of this. im very curious

[pixel8r]

ok when you are driving at what speed when the vibrations is at its worst? do you feel the vibrations on the sterring wheels or from the car seat? If its from sterring wheels its the front whels problem and if its from the seats its the rear wheels. Let us know. We have to get to the bottom of this. im very curious

the only time i really felt it through the car was on the dyno.

the vibrations got worse as the revs increased...but this could still be front suspension i guess.

Otherwise when just driving around i'd hafta say its mainly through the steering wheel and pedals, not the seats or anything.

My guess is front suspension or something in that area...

[66yostagea]

Could it be the Harmonic Balancer? Has the timing belt been replaced recently? If it has the balancer could have been stuffed bt incorrect removal.

You have to use a propper puller as shown in SK Diy section . If a three pronged bearing puller is used it could cause separation of the balancer if it was very difficult to get off.

[pixel8r]

Could it be the Harmonic Balancer? Has the timing belt been replaced recently? If it has the balancer could have been stuffed bt incorrect removal.

You have to use a propper puller as shown in SK Diy section . If a three pronged bearing puller is used it could cause separation of the balancer if it was very difficult to get off.

never heard of that...??

Timing Belt hasn't been replaced at all to my knowledge. Only done 37000kms and as far as i know it all looks genuine. What that means is the car has been sitting around for a very long time which i guess could be worse in some ways than a car thats done 10-15,000kms a year. But yeah the engine itself seems to run really smoothly.

The front suspension definitely could be better but its not a priority for me at the moment (drives ok still and i can live with it).

[66yostagea]

What about a GOOD wheel balance?

[IMPORTD]

I think I felt similar today going along the freeway.

I first felt the pedal vibrate then the rear felt as if it was shuddering slightly coming more so from the rear right..

I did it as I accelerated so I eased off, and floored it again to see if it would do it again and it did.. And it hasn't done it again.

I was thinking perhaps it was the road, like ripples or something, but I'm not sure..

I hope its nothing too serious.

It has been checked recently and front bushes need doing I think..