jumping out of gear can be a sign of your transmission needing replacement/ rebuilding due to general wear to the internal bearings and/or syncronizer gear surfaces. external causes can also be to blame, such as worn shifter stabilizer bar bushings, broken motor/tranny mounts, or worn/broken components in the shifting linkage. techcapri site has a troubleshooting guide that i used when mine did the same thing two years ago, unfortunately my tranny developed other problems soon after when the sycnronizers locked my tranny unpredicably into or out of gears at random! luckily russ had a tranny for me to swap out because it was real hard to drive in downtown traffic stuck in third gear! hope yours has a more innocent culprit!