driveshafts. The builder claimed he got a bad batch of input shafts from spicer. Anyways, the splines on the driveshaft itself were twisted. Only way to get it out was to force it further into the Trans with a mallet or hammer or lover the whole rear sub frame. Once you get the driveshaft clear of the differential you will have to use the mallet again to pound it back out of the Trans. I was pissed but fortunately the splines on the transmission were much harder and were not damaged. Good luck.