Vibration:( 85-110 km/h) in and out of 4th gear

Hi all I just drove to Bribie island from Mackay ~1000km

During the journey I heard a anoying rattle. I thought it was a empty soft drink can in the passenger wheel well.... About 2 hrs later I realized it was the gear stick ..... I touched it and it felt like a concrete vibrator at 110km/h.

I backed off in 4th gear and at 80 km it was kind of unnoticable. Then as I squeezed on the throttle it started to strongly vibrate ( the whole car) at about 85 km/h through to 110 very badly (like a harmonic balancer fell off) I pushed it further to 120 and even 130 but I sence the frequency of the vibration just increased it to a point where there was no harmonic and therefore less intensive a feeling.

I am running a decoupled now for ten plus years.
Previously I had a bad high speed/ high load resonating noise vibration which turned out to be a rear wheel brn failure.

My viscous coupling was emptied and filled with fiberglass 10 years ago. Never been a prob.

About 1 year ago rudi on Bribie swapped out my tailshaft as my uni's were on the way out. That was when he found the faulty rear wheel bearing causing the frustrating high speed resonating vibration.

I'm up set as I don't know the cause and I had a stressfull 14 hr trip.

All I did was rotate my tyres.
I have noticed the rear gear box front nose cone has developed a leak / weap.

What is strange is at 120 km/h in 4th the vibration is awful and if I pop it out of gear into neutral the vibration remains unchanged.

I'm thinking it has to be related to wheel speed.
Therefore brearings, cv's, diff gears dif bearings....tyres and tailshaft abd decoupled.

Any help would ge appreicated
Hamish dobson
0400792026

Sent from my iPhone
re "
I have noticed the rear gear box front nose cone has developed a leak / weap. "

Did you just grab the rear end of the driveshaft, at the nose of the trans ..
and try to wiggle it up and down  ..looking for play or damage there ?

that's what pops into my mind.
I have even read that it's slightly possible that having a decoupler there can contribute to wear at the nose of the trans.

I also can't help mentioning that one of the most brilliant things about a Syncro is AWD on pavement ..
besides generally improved stability (driving a syncro at 70mph on a local freeway, where I could shift in and out of AWD or 2WD it defenitely tracked down the road better in AWD than 2WD) 

And the other big thing ..
having the front and rear wheels gives a natural anti-lock affect to the brakes, a very good thing to have.

scott
turbovans.com 

On 1/22/2013 3:52 AM, MIKA wrote:
Hi all I just drove to Bribie island from Mackay ~1000km

During the journey I heard a anoying rattle. I thought it was a empty soft drink can in the passenger wheel well.... About 2 hrs later I realized it was the gear stick ..... I touched it and it felt like a concrete vibrator at 110km/h.

I backed off in 4th gear and at 80 km it was kind of unnoticable. Then as I squeezed on the throttle it started to strongly vibrate ( the whole car) at about 85 km/h through to 110 very badly (like a harmonic balancer fell off)  I pushed it further to 120 and even 130 but I sence the frequency of the vibration just increased it to a point where there was no harmonic and therefore less intensive a feeling.

I am running a decoupled now for ten plus years.
Previously I had a bad high speed/ high load resonating noise vibration which turned out to be a rear wheel brn failure.

My viscous coupling was emptied and filled with fiberglass 10 years ago. Never been a prob. 

About 1 year ago rudi on Bribie swapped out my tailshaft as my uni's were on the way out. That was when he found the faulty rear wheel bearing causing the frustrating high speed resonating vibration.

I'm up set as I don't know the cause and I had a stressfull 14 hr trip. 

All I did was rotate my tyres.
I have noticed the rear gear box front nose cone has developed a leak / weap. 

What is strange is at 120 km/h in 4th the vibration is awful and if I pop it out of gear into neutral the vibration remains unchanged.

I'm thinking it has to be related to wheel speed.
Therefore brearings, cv's, diff gears dif bearings....tyres and tailshaft abd decoupled.

Any help would ge appreicated
Hamish dobson
0400792026   

Sent from my iPhone