Hey i have a 86 fc rx7 and when ever i jerk the car around i can hear i clanking underneath the car but ive looked under it and checked if anything was loose and there wasn't anything also the car vibrates a little more when driving high speeds (usually on the freeway). I'm thinking it could be my u-joint on my driveshaft? could that be it? and if it is would it be easier to just find a good condition used driveshaft with a good u joint and put that in instead of replacing the u joint because i believe the u joints are not replaceable??

 

Likely u-joints, and/or a broken front diff mount.

U-joints are not replaceable, so either have a local driveline shop make you up a new shaft, or buy an aftermarket one from Mazdatrix.

 

my local engineering shop will take my old shaft, 88 vert, bore out the yokes and press in bearing cups of a common size