tl;dr - Car started popping out of fifth gear and I'm trying to decide if it's safe to drive to a dealer 800 miles away.
After a lot of forum lurking, it's unfortunate that my first post is in the 'Troubleshooting' section, but here it goes:
A month ago I bought a 2011 WRX with 15000 miles. After putting about 500 trouble free miles, I decided it was safe to do a road trip to see family in Oregon over the holidays. On hwy 95 in Nevada (truly the middle of nowhere), the car suddenly popped out of fifth gear. It then proceeded to do so for the next 200 miles, at a frequency of every 2-30 miles.
It only happens in fifth gear, and nothing specific seems to reproduce it. Happens while in and out of cruise control at speeds between 65 and 75, and not only when decelerating or going over bumps. I haven't found anything to consistently reproduce the issue.
Now, I'm wondering if this is something that I need to get fixed by a dealer in Oregon immediately (which presents great logistical challenges not worth getting into, mainly because I'm far away from any Subaru dealer), or if it won't damage the car and transmission further to drive back to California and visit a dealer there. The car is still under warranty.
Based on what I've read on the forums, the root cause of the issue can be the engine mounts, transmission fluids being low(?), problems with shifter bushings, sequentials, or other worse transmission problems. I'm having a mechanic put it on a lift tomorrow to check for the engine mount issue; is there anything else I should look for? Thanks for any advice.