I don't know what it is, but mine feels like it is barely in reverse sometimes. It has never popped out, but I usually hold it there 'cause it feels like it going to. Once in a while I let the clutch out and it isn't in reverse...it really pisses me off, I hate hearing the grinding noise of gears and knowing what it does to them! I am removing mine this winter and shipping it off to RS Gear to have them go through it 'cause I still have a problem w/ my 2nd gear synchro.