i *think* my Z developed the shifting/knocking noise driver seat again. im not 100% sure as it only felt like it happened once today, and i couldn't reproduce it when i got home. last time i just hammered in the stock star washer (push nut) into the shaft using a 12mm or something impact socket and mallet...and it worked for the last 3yrs.
this time i ordered the TSB replacement pushnuts and will keep it in my parts bin in case it did resurface again.
price of parts is like $2 which is a ripoff, but the freight is $17.
i just had to laugh.
