Join Date: Oct 2003
Location: Evansville, Indiana
In short, no, a bad CV will not cause the car to "miss/jump out of gear"
Sounds like you may have mulitple issues going on by your description.
"Hard shifts and clunking", along with strange "vibrations" at speed could very well be the CV's, mounts, etc., but "missing shifts/falling out of gear" is almost certainly an internal issue with the trans.
Sorry for that news, but welcome to the site none the less, and good luck on any possible attempts of fixing.
Lots of good folks here to help if you decide to go that way instead of the bayou.