4th gear going out?
anytime i shift into fourth at WOT, or actually anything above 2k rpms, it pops right out of gear, doesn't do it in normal driving, and there is no grinding noise, it just pops right out. also, if i am in 4th, put in the clutch, rev to 1800+ rpms, and pop the clutch, it will pop out as well. any ideas? 
