Volvo: 1998 XC70 driveshaft, v70 xc, bremen germany

Question
Hello, I have a 1998 V70 XC with driveline issues.  I needed to replace the driveline due to a torn mount on the middle carrier bearing, but as you know they are only full replaceable and I wasn't prepared to spend the amount of money needed, so I devised my own mount out of WEICON ( a building material) and it works quite well.  I put the driveline back in but now have a very nice vibration more around 30-50 km an hour.  My main question is, which way should the driveline go?  I am hoping that the mechanic stuck it in backwards and therefore, the vibration.  I am also aware that, in the front where it connects, there is a slight bit of play...could this be the culprit?
Also, how damaging is it to drive with it like this?  I have been told that it could ruin my transmission, which is a definite no no in my book. ( out of the frying pan thing) I will pull it this friday if I need to,assuming that it passes the local TUV inspection.(BTW, I am in Germany.)
Thanks for the info.
Best Regards,
John McLoughlin
IS Bremen, Germany

Answer
John,
The short shaft goes forward, and if the halves have come apart there is an arrow to line those up. Is there a driveshaft shop that could balance the shaft if you carried it in? I would limit the driving I did until I got rid of the vibration. I never heard that the vibration could damage the trans, not real sure how!