: Continuing vibration problem



mhemsley
10-01-11, 05:41 PM
I posted about this problem some time ago and received some very helpful information, but the problem persists. Here's the problem, then I'll go through the chronology of dealings with the dealer (the car has a Luxury Warranty good until August 2012).

The car is a 2006 V. I bought it in March and have put 13,000 miles on it (now has 71K miles). I was not able to test it at speed before I bought it and was seduced by the warranty so didn't press the issue. I have only driver 3 Vs and none at speed so I don't know if this is a general problem or something with my car.

Problem - a vibration that I can feel in the steering wheel and see in the interior rear view mirror in 6th gear at 2000rpm and above. When I first get to 2000 rpm in 6th, I also feel it in the seat and floor, but that seems to go away after some minutes (5 or so). It does not happen in any other gear at 2000rpm and above, and it does not happen at the same speed (70+mph) in 5th gear. I have taken the car to 80-ish mph repeatedly, and the vibration persists but does not get worse. I am not prone to driving at high speeds, but recently I needed to get past a problem driver and took the car to 90+; when I glanced at the mirror, it was clear at that speed. The vibration stops as soon as my foot is off the gast.

The dealer's service writer has worked hard to convince me not to make them pursue the problem, but I'm not easily persuaded to accept this vibration. They have replaced a number of problem items under warranty, not all related to the vibration (oil pressure sender, clutch master cylinder, oil temp and level sensor), and others supposedly causing it - harmonic balancer and flywheel. I had the clutch replaced when they did the flywheel (paid for parts only). They claim to have checked main and rod bearings when the engine was out and there was no problem. When I picked up the car, the service writer said "it is smooth as silk." It wasn't - same vibration, although possibly marginally better.

I had a friend who is very mechanically astute feel the vibration. He has run the maintenance facility for several major trucking firms and is good at diagnosing problems. Unfortunately, he was puzzled - nothing is obvious. It could be as simple as as the body responding to a harmonic set up by the exhaust under the engine load in 6th at 2000 and above.

The dealer claims to have test driven the car, but I don't believe it and am going back to have a mechanic ride with me and actually feel what I'm talking about. Because the dealer is so reluctant to pursue the vibration unless pushed, I'd like some additional thoughts about what might be causing the vibration. When I last posted, someone (thank you, whoever you were) pointed me to some tests for driveline vibration that I gave to the service writer. I suspect that is what led them to replace the flywheel.

When I complained that the vibration was still there after the flywheel replacement, the service writer suggested that it might just be my car, then added it could be the driveshaft - this guy isn't terribly sharp.

So, two questions:

1. Anyone else had this or a similar problem?

b. Any ideas what I should suggest they consider as a cause of the vibration?

Thank you for whatever help you can give me. The V is a great car, and I enjoy everything about it, except maybe the shifter. I'd really like to solve this vibration.

Mike

wcryan
10-01-11, 05:48 PM
mine just vibrates from about 70-85. I'm gonna get a roadforce balance and i'll keep you updated. People say our car is really sensitive to balancing

darkman
10-01-11, 06:02 PM
It is true that most high-speed vibration issues ultimately involve the tire and/or wheels. It is also true however, that when a vibration issue in 6th gear cannot be duplicated under like conditions in 5th gear the issue is the weak 6th gear mechanism particular to the Tremec transmission more often than not.

If you have not tried new tires or force balancing the existing tires it may be worth a try. My bet however, is that your transmission is the culprit.

http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-general/232660-top-gear-vibes.html

trhs75
10-01-11, 06:10 PM
My money's on the transmission. That's what happened to me as you've probably seen in another thread. My tranny was replaced under warranty. Is yours a GM warranty? They may be better about taking care of you than a 3rd party warranty might.

mhemsley
10-03-11, 12:10 PM
Thanks for the replies. I'm going to push the transmission issue - I've heard about 6th gear in my earlier post.

It is a GM warranty (no longer offered but still respected), so I hope they'll be agreeable to look into it. If not, I'll start pushing the problem up the chain from the dealer.

Again, thanks!

Mike