Okay, so I did a search and did not find anything really that describes my problem or a potential solution. I just installed a 6-puck ACT clutch with heavy duty pressure plate about 500-600 miles ago. I figured the problem might go away after the clutch was seated and such. No such luck. It is a vibration/rattling at I would say around 3000 - 3400 RPM in 4th gear and sounds like it is coming from the transmission or front bellhousing area. If I go moderate throttle or WOT it immediately stops and I can only make it occur under real light throttle also sometimes coasting. The RPM figures might be slightly skewed as I am at school and have not driven it in about two weeks. If you guys need an exact figure I can go drive it for a bit, but I hope I have provided enough information.

 

Bump.

 

I just thought of something else. Could it possibly be resonance from the exhaust on some of the heat shield under the car? Come on guys, I am sure someone has an idea what this might be. :/

 

Bump again.

 

well my exhaust rattles a bit but I know it is one of the hangers that is a bit loose but i have not had time to tighten it up. My shifter used to rattle before but went away.

 

My shifter rattles too when I am accelerating usually. I can hear that in the cabin just fine, but this sound is way lower than that and I can actually feel the vibration in the car, especially if I touch the area where the bellhousing is.

 

maybe it is a broken mount?

 

Well, when we reattached the transmission all the mounts looked fine to me and the guy that was helping (who is a licensed mechanic). But, even if it is why would it only occur in 4th gear given a specific RPM range? Are vibrations and stuff like that that funny?

 

nah in that case I would think something went wrong with the clutch job or something along those lines. We need some guru help hear.

 

Ok, this has happend to me. And it's kind of funny. The vibration is coming from your drive shaft. Why is it doing this? I don't know. But you need to lift the car. Take off the drive shaft. And reasemble it, making shure the bolts to the diff. are very tight.
If problem still occurs. Replace it.
Problem solved.

 

Alright, although we made sure the bolts were tight upon reassembly the first time I am not ruling out the fact that the harsh engagment of the 6-puck could have caused it to come loose. I will try to do this sometime this weekend. Do you have an idea what is worn that would be causing the vibration or is just because it might be loose? Thanks for the help so far guys.

 

Bump, just to see if anyone has any more ideas/suggestions.

 

I can't think of why a new clutch would cause that. Sure the clutch isn't somehow unbalanced or something?

 

I do not believe it could be unbalanced. I mean it is ACT and they are know for making quality parts and not screwing stuff up. When we installed it we did our best to be ginger and thorough about everything too. Also, it does not explain why it would vibrate at that specific RPM ranger either. I guess I am going to just have to go with the driveshaft idea and try that for now.

 

Just try your drive-line. I know it sounds weird, but it worked for me, and others 7 owners on an other thread.