Alfa 1300GT junior 1970 driveshaft
i have had some work done on my car's driveline as i had some vibrations at around 60mph (100kph) coming from behind.
now it seems solved but since then I get a louder/deeper resonnance between 35 and 50mph (60-80kph)!
they replaced many parts on the driveline : bearings, supports etc, including a part of the propshaft. they put one with 9mm screws instead of the 8mm that was in place, assuming it was a mistake.
My car is a 1970 1300 GT junior, kind of transition year, so 1st series body, floor mounted pedals, but 2nd series dashboard. so the questions are: which propshaft should be mounted? can it be the cause of this vibration?