my steering wheel was doin the same thing,
my bro works for nissan, and he got me the bush but i dont have part no.
it was a rubbr bush with like a nylon sleeve in it, and also a metal bastrd with a few holes and slots in it.i couldnt figure out where the metal one went so i didnt bother with it, but the rubber one didnt quite fit all the way in so i had to chop it in half and stick about 2cm into column.
may be a bit dodge, but it solved the prob, and its been tight as a tiger ever since.