help
1. sounds like the needle is binding up. Probably have to take the whole thing apart to see whats going on in there. Does the odometer still register mileage while the car is moving? There is really no direct drive for the cable to the needle, it's a couple of magnetic fingers that spin around a "bell" that the needle is connected to.
2. When you have the gauge cluster out you'll be able to see the vent tube on the drivers side and with the glove box liner out you can get to the passenger side... or you can cut up your arms trying to squiggle your way up to them from the underside...who am I kidding... you'll still get cut up going thru the front of the dash too :)