RedNed seems to have the exact same thing. I checked the axles and boots and everything seems normal. The vibration is different in different gears. I get the vibration worst when I'm above 3500 rpm in 2nd and 3rd. I get some vibration in 1st, 4th and 5th too - but not like 2nd and 3rd. Sounds like RedNed has the exact same thing going on. I didn't talk to the previous owner because I bought it at a dealer. I don' t know if its always been like that. I just shift now at fairly low rpm and it doesn't bother me much.
Hyraulic Valve Lash Adjusters... ahh... HVLA - (I can feel myself getting sucked into the lingo!) I'm definately going to try the CD2 Oil Detergent. I'm already using 10W30, so that makes life a hellova lot easier. If that doesn't satisfy me, I'll try rebuilding the oil pump and fixing the check valve.
Rad.. Thanks for the ideas!