I am getting a little bit of a vibration coming from the midsection of the car (under acceleration) at 2k rpm in 2nd and 3k rpm in first. no other gears.

i recently replaced the drive shaft but did not have this problem for the first couple months with the new shaft. is it possible a balancing weight fell off?

when the first shaft went, I only got vibration at high rpms not low.

thoughts?

 

Anything is possible I guess - but I haven't seen balancing weights on any modern driveshaft. They usually auto-balance them by adding some weld material where weight is needed. Was this a new or rebuilt shaft? In any case - it should be under warranty from whoever the source for the shaft is..