I have a vibration in my car win I get a round higher speeds, I gust got 4.10 gears installed and it has made it way more noticeable the man that installed my gears is a 35 year pro and said it is more than likely in my drive shaft, has any body had the same problem?
It's not uncommon to have a vibration after a gear install. IT's more than likely always been there, its just the higher gear ration brings the vibration to your attention sooner since the RPMs arrive quicker. It very well could be your drive-shaft or just a bad U-joint. Either way an aluminum drive-shaft is a great upgrade because it is freshly balanced, comes with new u-joints plus the lighter weight aluminum will help with your rotational mass and in turn free up some horsepower.
It was my problem. I have an 86GT with 4.10s and it would feel like the tranny was going to come through the floor board when I went about 70MPH. The 28 spline aluminum FRPP drive shaft did the trick. I have had it way too fast now and never felt a vibration again.
On a similar note, my 97 Cobra vibrated too above 57mph after I put a FRPP 3.73 rearend in it. The driveshaft was checked for balance and was dead on. Put the 31 spline FRPP aluminum driveshaft and now it is smooth up to as fast as I want to go. This may have been more the harmonics of the steel drivehaft versus the aluminum. love both and would never switch back.