I recently had the 3in aluminum driveshaft installed but the guys at the shop said that the yoke wouldn't fit/go in so they just used the old one, is that normal and would it make puting in the 3in shaft pointless cause the balancer is not on there?

 

You mentioned the balancer, would the aluminum shaft be from a Camaro LS1? If so it is a direct fit into the '91 with the 700R4 (or T5, or T56). Unbolt and remove the OEM shaft, slide the new shaft in and put the bolts back in (4 bolts for rear U-joint to differential yoke straps). About 10 minutes worth of work.

RBob.

 

Dont forget to drain the trans beforehand. Makes a mess when you pull the D/S out.

 

The driveshaft is from a 97 firebird, i also thought it should be a direct bolt in, but the guys from the shop who installed it said the yoke would not fit so they had to use my original yoke, so would not having the balancer on the new driveshaft not cure the vibritation problem?