New Clutch - now new vibrations at certain RPMs

[McFly]

Got my clutch replaced a few weeks ago - Luk brand clutch kit for my 2000 V6. They also resurfaced (ground) the flywheel. It shifts better, better pedal feel etc. but I have some new vibrations that I never had before.

At approx 1800-2000 RPM there is a buzzing type vibration that sounds like it is coming from the transmission/engine area. It is only heard when accelerating through the gears when they hit that RPM range. It vibrates the floor under my feet and I can feel it in the seat as well

In 3rd and in 4th gear I now also hear what sounds like gears or synchros vibrating when I am accelerating, but again only during certain RPMs. 5th gear just has more all around vibration but definitely a lot more than before.

They re-checked all the bolts and they are tight. I checked the trans fluid level and it is full.

So my question is - what could be causing this vibration?

I am thinking it has to be the flywheel. When they ground the flywheel surface did they mess with the flywheel balance? I know I have an early 2000 that has the externally balanced flywheel. Was it put back together wrong and the flywheel weights are now messed up?

Any help would be much appreciated!

 

[bill302]

check your balancer ensure the rubber within the balancer is in good shape and has not slipped...also you might want to see if the driveshaft was marked at the pinion and bolted the to the pinion in the same position as it was before removed..

 

[02ponypackage]

seems like on point advice....... and for bill302 what nitrous shot are you using ? my buddys 97 GT has less mods then you and runs a 13.5 with a 50lb box in his trunk on street tires and the track isn't ever really good at Bithlo at aka Orlando Speedworld

 

[bill302]

90 shot and my problem is traction i launch at 2000 rpm's to keep from spinning all the way down the track my next mod will be drag radials which should put me in the 12's by being able to launch at 3500-4000 rpm's....

 

[speedytang]

Do you feel the vibration when not moving? clutch in or out or only when moving.

 

[McFly]

I don't think it is the flywheel. There is no vibration when it is in neutral in that RPM range. I am convinced it is the driveline after reading this similar Service Bulletin:
http://www.stangnet.com/images/stories/docs/sn95_TSBs/01-08-03.pdf

I had 2 guys ride along with me yesterday. One says I am shifting too early! but for 120,000 miles I never heard a vibration like this- only after they had the transmission in and out. The other guy didn't know what it could be, he said maybe exhaust or something. 1800 RPM in 3rd and 4th gear is NOT shifting too early. Cruising up a slight incline in 4th gear from like 1600 to 2000 RPM makes the gear sounding vibration louder.

I need to crawl under and look at the paint dots to see if things are aligned or whatever. I am taking it back in Friday to the trans shop. They need to investigate this driveline balance stuff. Its just frustrating!