I used to own a DVR. Sometimes the top of the index pin used to get
clogged with debris and had to be taken apart and cleaned.

Also, using the index pin to lock the shaft when unsticking a really
stuck chuck can break off a tooth from the index wheel. I know
because I did that. Teknatool told me that they would replace it,
once. They recommended not doing that again and said it would not be
covered under warranty a second time.

Ted J
thelatentlog.com