Unable to Change Time or Date of DJ

[vincennes02261897]

Hello,

After not having worn my Datejust perpetual (16233 I believe) for a few days, when I took it out yesterday, the time needed to be reset. I unscrewed the crown and pulled it outwards to change the time like I've always done. After changing the time, I proceeded to change the date. Pushing the crown in all the way, and pulling it back out to the first stop I began to slowly and softly turn it to change the date. Unfortunately though, it seemed stuck. Because I didn't want to risk hurting anything, I did not force it and instead I pushed the crown back inward and securely sealed it back.

When I looked at my watch later, I realized that the time wasn't working anymore. The second hand wasn't even moving.

Today, I took it to an authorized Rolex dealer to be looked at and I was told that the ____________ was stripped. To repair the watch would take about a month because the watchmaker is backed up and it would also cost around $550 for the repair and a cleaning.

My questions are as follows:

1.) I didn't catch the term for the part of the watch that is stripped. Can you help me identify this please?

2.) Would this be a fairly simple thing to change without much experience with watches? I'm a do-it-yourself kind of guy and would certainly be favorable to saving the money if at all possible.

3.) Does the above-mentioned cost seem reasonable for the repair?

4.) Is this a fairly common thing to go wrong?