A quick search says the gears are 2.66-1.78-1.30-1.00-.68od. That's a pretty nice progression of ratios. Would work well with a teener and 4.10s you bet. I like those splits. But,I wouldn't like that shifter;For me it seems; too short, too cramped with the lift lock on it, the ball is too small and too slippery.and it appears somewhat notchy. Minor glitches I can fix..
AS to vibration, look to the driveshaft or rear pinion angle before you get too excited.
As to gear noise, make sure the trans and shifter is not touching anything it's not supposed to.
If you already tried that, then, if you put synthetic in there, I would swap in some 85/95 EP oil and see what happens.
