Trying to determine if I have a problem Houston

[ciaka]

So about a month ago, the drive shaft went on my car.

Purchased a reman shaft from a shop in CO.

Replaced according to service manual instructions. Also replaced the flex disc with the install.

Did not use the alignment tool for the bearing but made sure it was the last thing to tighten up (after playing with it to make sure it settles into a neutral position).

After replacement, all seemed fine when driving regularly (no sudden accelerations, etc).

I took the car on a road and tested fast acceleration in a straight, and noticed a small amt of vibration. Repeated 2 times more to verify. All was done at night. Got me concerned.

Emailed the company thinking I may have an unbalanced/bad? shaft (they replied to call but I did not do so yet at that time).

However, took the car on the same road during day and noticed that the road has some small ripples near side of road, which to me would explain the vibration, especially if one was to drive fast on that road.

So I explained the vibration with those ripples.

Took the car to a different road. This time on hard acceleration in a straight, there was no vibration at all, even with the pedal all the way down.

Repeated several times, and each time same result - no vibration.

My thoughts were, all is fine, all is GOOD!!

As a preventative measure, took the car to my tire shop to do all tire rebalance plus tire rotation.

After driving some time (maybe couple weeks), I happened to accelerate into a curve fast, and noticed similar type of vibration appearing again. Got thinking again.

Tried to repeat. In straight line, nothing. Curve, nothing.

It appears as though the vibration happens intermittently. I am trying to determine whether it may be the shaft, etc. I plan to crawl under there again to visually inspect bushing and realign again.

The vibration is subtle, noticeable and comes from somewhere under the car I assume (not guaranteed center of car, but kind of felt similar to shaft only very subtle), when it does decide to appear.

QUESTION:

Does anyone have any further suggestions for troubleshooting, to help determine if I do have an issue? I do not particularly feel like spending another 500 on another shaft (even though this guy does have a 1 yr warranty). I am confident the install was proper (I am a very meticulous person to do any work on my car - do it right not fast).

As always, help is much appreciated. Thanks in advance.

[wvicary]

If the shaft was the problem it should be doing it all the time, not intermittent, speed can play a factor but it is also consistent. Have you inspected the front lower rear control arm bushings or any engine mounts?

[mudman2]

It does sound like the shaft still

if you say the word

"wummering" over and over does that match the vibration pattern ?, also what speeds

[ciaka]

i have had a hard time trying to reproduce this. Very seldom.

Was able to repro a couple times when accelerating in a turn (hard acceleration).

Was able to repro once I think when going straight (again, hard acceleration).

Did not manage to look at speedo but it was with foot down on gas.

When I reproed each, I tried again, and each time was unable to replicate (not able to replicate successively one attempt after another to obtain the vibration).

I am still thinking it may be the road conditions????

How does the traction control work on the CTT? Does it apply brakes when accelerating? Is it possible the vibration I am feelling can be coming from the tires momentarily losing grip and the car trying to adjust the power?

I am on Vredestein sessanta tires, and those suckers provide a ton of traction when needed.

During normal driving, I do not have any vibration on steering wheel, no imbalance of any sort, which would imply control arms issues, etc.

The vibration sounded very small, but similar to the shaft noise that I heard when that went (much subdued though, and under hard accel).

I was thinking of the following plans:

1. Crawl under there again, loosen up the bushing mount screws to see if the shaft realigns itself to a different position than it is in now.

2. Asking the company to send another shaft in

However, I wanted to run by you fine folk here for ideas/help.

[ciaka]

OK.

While doing my TC fluid change, got a chance to inspect this shaft thing again.

I loosened the bolts holding the bushing to bearing bracket (before I did so, I marked the areas to see if after realignment, there was any difference).

Made sure the bolts are nice and loose but did not remove all the way from holes.

Using both hands, moved the shaft in all directions, and also reached up there to move the bushing itself while shaft was being moved. The idea was to let the shaft settle into a natural position.

Marked the location of bolts before started to tighten them, so during tightening, I know where they need to be.

After the process, one of the bolts seemed to be about 1mm more towards rear than it was originally.

Tightened them all nicely.

Took to the road, and tried a few hard accelerations - some in a straight, some in a turn (hopping to reproduce the subtle noise).

I was not able to reproduce the noise at all. Tried a few times and no luck.

I will keep trying once in a while to see if the noise comes back. The realignment seemed to be miniscule but who knows...it may have made a difference. For now, no noise. I will update if that changes.