My friend has an '88 Toyota p/u, 22R-E, manual transmission, 4" suspension lift, 3" body lift. The truck has a tendency to pop out of gear on its own, especially first, when under load. If you hold the shift lever in place, it will stay in gear, but once you let go and get on the gas a little bit, it will pop out into neutral. It shifts into gear just fine, it seems. There is no shift boot or anything that might touch the shift lever when the driveline moves. A search on 'transmission popping out of gear' didn't yield any good results. Anyone have any thoughts on what the problem might be?