My 92 SVX has several annoying problems that I just can't seem to fix. Any thoughts?

1. The oil dipstick doesn't seal properly. Every time I open the hood, the dipstick is sticking out about 2 inches. It seems like there is a plugged crankcase vent somewhere, but I havent been able to find anything. The hoses coming off the valve covers aren't blocked...

2. The seatbelt light on the dash stays on all the time. The belts work fine otherwise. Is there an easy way to disable the light short of removing the dash? Where is the sensor that detects when the belts are locked?

3. The not-so-minor intermittant problem: At least half the time, under hard acceleration there is a terrible vibration coming from under the car, probably the tranny. It's as if I'm driving 40 mph down a dirt road with 6 inch ruts. I discovered that the problem goes away if I put in the fuse to override the AWD, and that worked fine for a while, but now it is starting to do it even in FWD. Am I losing my transmission? Each time I take it to the dealer the problem magically goes away.

Thanks for any ideas.