Pete stubbs

Hi all, I'm new to this forum, and I need help. There's a whining noise from underneath, that now also has a clicking, chattering sound, the local garage reckon Vic, and Ird. I got a replacement ird, and waiting to get it fitted. I had a look at the pinion shaft, and all the teeth look good, and no bits in the oil, would the pinion shaft be shot, if the Ird was at fault?