5th gear issue / clicking issue

[Rickinnocal]

Hello again :-)

Thanks for the help with the smog issues, I got my sons 86 Bronco II w 2.9 V6 to smog well below averages.

Now, though, there's a new issue has cropped up. Now that it's running right, he has taken it onto the freeway, and been able to try to shift into 5th gear - but it won't stay there. It runs fine in all other gears, but if you put it in 5th it jumps straight out. If you try to hold the gear lever into 5th you can feel the gears trying to kick it out.

What should I look at?

The second issue I think I know, but would ask if anyone has any other ideas. When the engine's been running for long enough to get hot it starts a 'clicking' noise that speeds up or slows down with engine RPM, and the oil pressure light goes on and off. I suspect clogged oil drain-down ways trapping the oil at the top of the engine. Any "I agree" or "No, check XXX instead" guesses?

Richard