Stopped at a light the other day in the 505 with SR20DET and I put it in gear and there is a loud grinding noise and no forward progress. Thought it was the Nissan gearbox which has been becoming progressively noisier over time finally giving up the ghost.
I had it towed into a Jap import workshop that had a SH box and was willing to install it for a reasonable amount. He rang me later to tell me the solid tailshaft inside the torque tube was totally stripped bare of teeth where it mates with the gearbox output shaft! He said he had never seen this happen before. This is the tailshaft that I had the 505 stub sawn off and a Nissan stub welded on by a tailshaft workshop so that I could mate the 505 diff with the SR20 gearbox.
It surprised me too especially since the other end of the shaft which is all std Puegeot was still OK.
The only thing I can think of which might cause this would be a misalignment of the tailshaft with the output shaft of the gearbox. When I had the 505 flange welded onto the Nissan box so that I could bolt up the 505's torque tube to it I did not think it necessary to have the surface of the flange trued afterwards, to make sure it was absolutely parallel so I am having this done now while I wait for the new tailshaft to be welded up. Anyone have any other ideas for what could have caused this? A faulty Nissan stub seems possible but unlikely and the tailshaft place assures me the welding process does not weaken the stub.