Drivetrain vibration?

[GTS-t VSPEC]

Hi Guys,

When I'm travelling down the freeway doing 100km/hr , yes I do occasionally stick to the speedlimit, and transfer from 4th to 5th then I get a vibration in the car at any non-idle revs.

I have a twin-pate clutch in the car and the vibration feels similar to when the plates knock together if you have the revs too low and are going to stall. I don't think it is suspension related as in 4th doing the same speed it doesn't occur.

I have a couple possible theories that I would like people to comment on if they have had similar experiences:

1. Could it be the synchros in 5th gear?

2. Could it be the diff?

3. Could it be the clutch?

4. Could it be the lightened flywheel?

I had heard that if you get a lighter flywheel then the harmonic balancer may need upgrading, I have no idea about this so would be grateful for any feedback.

Thanks.

See'ya:burnout:

[fatz]

flywheel

had the same problem

at about 2300-2500 is got a vibration

i replace the gearbox twice for no reason trying to find the problem

but it was the flywheel

pete

[Cubes]

I have a vibration from 100 to around 120km's.

It was there with the std flywheel and now its still there with the lightened flywheel.

Maybe the Tail shafts center bearing?

Its only in 5th gear though?!?!

At the same rpm in lower gears the vibration is not there.

I also suspect my gearbox as it has had a input shaft bearing whine since i've owned it.

Possibly causing a little slack?!?!

Who knows..

[GTS-t VSPEC]

Thanks for the reply Joel and Fatz. No it doesn't vibrate in any gear other than 5th. I am leaning toward the flywheel as the culprit aswell. What did you do to fix the problem Fatz, have the flywheel balanced or have the harmonic balancer replaced?

Thanks for your help with this guys.

See'ya:burnout:

[Brody]

I had a similar problem because when i had my flywheel lightened, they ****ed the job and it was unbalanced.

If ure problem only happens from 4th -> 5th it may not be the flywheel, AFAIK, u should feel the vibration when reving not in gear.

[GTS-t VSPEC]

Thanks Brody,

I am having my crank polished and balanced so I'll get them to test the flywheel at the same time, it's the best option I have at the moment.

See'ya:burnout:

[Hicks]

Who's balancing your crank??

How much does it cost and what benifits do you get??

Catch ya,

Ben.

[GTS-t VSPEC]

Hicks,

This is at the same time as I get the forged pistons in, bore the block and shotpeen the conrods. The benfits are that once it is balanced then I can rev harder, and it need to be done with the forged pistons as they weigh less than the factory items.

See'ya:burnout:

[Hicks]

I have to say, Your cars gonna be runnin hard when your done.

If only I had the money.

Hmmmmm, selling drugs brings in a bit of money..........

[GTS-t VSPEC]

Hicks,

So does being a pimp!

See'ya:burnout:

[blind_elk]

Since it only happens in 5th gear, then it seems logical that its something to do with 5th gear.

If it was flywheel or input shaft, etc, then it would likely happen in any gear.

My guess is a bearing on the 5th gear layshaft is on its way out.

[Cubes]

Blind_elk..

That is what I figure.

Especially when i can hear my fifth gear whining.

[GTS-t VSPEC]

Hi guys,

It's not like I use 5th alot, so should I just ignore it? What about using the Redline Shock Proof oil, will that help or not?

Thanks for your input.

See'ya:burnout:

[fatz]

never put the clutch back in but when i rebuild it i will get tha flywheel balanced go from there

[ix9]

Gtst-VSPEC

I have the SAME THING..!!!

Only I KNOW my 4-5th Synchro is rooted! It kicks back pretty badly. It's going in this afternoon to have it fixed, still got 3mth Stauatory warranty.

As mine only does it in 5th Gear, I too assume that it's 5th only... either way they're gonna fix it. I'll let you know how I go with it all.

-Kym.

[GTS-t VSPEC]

Strich9ine,

Is your in the transition between 4th->5th or when it is in gear? Mine is when it is in gear, therefore I don't think it is the synchro, I think that it is either the 5th gear or the flywheel. Let us know how you get on anyway.

See'ya:burnout:

[ix9]

Originally posted by GTS-t VSPEC

Strich9ine,

Is your in the transition between 4th->5th or when it is in gear? Mine is when it is in gear, therefore I don't think it is the synchro, I think that it is either the 5th gear or the flywheel. Let us know how you get on anyway.

See'ya:burnout:

My transition from 4th-5th kicks back horribly... above 130km/h+ tho..and when changing quickly....

... then all of 5th gear i get that vibration noise....

hence i said before I KNOW my synchro is faulty, as it kicks back when changing... that may be causing the vibration in 5th gear ?

It's in for repair, I'm without a car for a few days