Vibration location???

I have a slight vibration that I feel at various times at 2k-4k rpm at part throttle and at times feel it in teh steering wheel while cruising at about 2500 rpms. All tires are balanced and car was professionally aligned. It is not always there. I am frustrated at locating this. I am running a MII front end and zz3- tremec with centerforce dual friction clutch. Clutch and flywhell were brand new when installed. Vibration does not seem to be in the shifter. Thanks

Almost sounds like normal road vibration. Can you reproduce it one the same road and lane?

Could be a wheel bearing..

Might want to try having the tires load balanced. A guy I know had a wierd vibration in his vette and had this done (some call it force balanced) and the vibration was gone. His vibration was speed related and NOT related to engine rpm though.

Check the u-joints.

Its radial force vibration-aweak spot in the tire that causes the reverse of a buldge or belt seperation.

Ok i worked at Sears Auto for six years and dealt with this problem every day . I would have the tires checked again for balancing at another location (their machine could be out of caliberation)but just do the front two because if the vibration is in the steering wheel its the front.While the tires are off have them check the tires for any hopps or side to side motion(all tires have a slight movement) and wheels for warpage and please dont say their ok cuz i havent hit anything it does not matter ive seen brand new wheels out of the box that were warped.Check you air pressure sounds stupid but ive seen it before.
If you are all good on the wheels and tires then make sure when they did your alignment they check to see if your tie rods,idler arm,sway bar links ect.ect. are all tight, that should have been checked before the align. but you would be suprised the people that dont check that.
If all is still not well start looking at the driveline.
Hope this helps.
Later Matt

I know this may sound weird, but what shape is your transmission crossmember mount in?

I had a weird vibration just like you described. Rebalanced all my wheels, new u-joints, 2 driveshafts ... even had one of my driveshaft checked for balance. Retighten transmission mounting bolts, engine mounts ... everything.

After stripping my transmission mount, I went out and spent the $15 for a new one and the vibration was gone. 2 years of agressive, over $15 mount.