Shifter popping out of 2nd gear

I can't answer the first part of your question.

For the second part, I had the opposite problem where shifting into 1st and reverse even with the clutch fully depressed caused a bit of a grind, but it's fixed now.

If you have someone press the clutch, can you see the clutch slave move the clutch arm? If it isn't moving, I would suggest replacing the brake fuid in the clutch line making sure you bleed the air properly. Then check again to see if the clutch arm moves. You can also make some adjustments at the clutch slave.

Brake fluid and new long throw clutch slave are both relatively cheap.

Worst case is needing a new clutch, I don't know the cost involved with that, as I haven't needed it done yet. Good Luck.

I was having the same problem, popping out of second gear. It started right after I installed a new shifter rubber boot in the console that I bought from Hall Pantera.

Took the boot out and it stopped. If your boot is new, this could be your problem. The after market ones don't seem to fit evry well and are to tight.

If not, check your shifter adjustments. Has to start centered in the gate, side to side and front to rear. Are you sure it's engaging second all the way ?

Otherwise, as we've all done, check you salve adjustments for the gap through the ZF sight hole when the clutch is disengaged. You need at least .40 clearance if not more. Make sure there's no air in the system and everything is functioning.

If the problem continues, you may need a new Salve or Second gear. In which case, ouch....Second gear wise.
As GR8 said, get the long throw if you replace the salve. PI's got some nice ones, call Jerry.