Engine noise/gear range...any insight?

[abxy1982]

I've been driving a '76 530i for the last week or so that I sort of inherited. It might just be me, but there are a couple of things I've been wondering about.

The car, in general, seems really loud to me. Not like the muffler's going or anything, but just louder than usual. I'm guessing it's because I'm not used to driving without all the insulation of a newer car.

While the car drives well (I drove it 300 miles on Monday to my house and a 160-mile round trip yesterday and this morning), it does seem like I go through all of the gears by the time I hit 35 mph. If I leave it in 3rd much past 30 mph, the engine's already at 2000 rpm and it just sounds like it's laboring. I feel like I've got the handbrake on or something, but I don't. Maybe that's normal; like I said, I'm not used to the car yet, and it's been a while since I've driven a manual. Is 3rd gear's range always that low for these cars? I just want to make sure I'm not doing any damage. In 4th gear, though, on the freeway at 65 mph, the rpms are only at 3200 or so, which seems fine.

Last thing, I've also noticed a bit of a buzzing noise when I first turn on the car. It's in neutral, handbrake off. Sounds like it's coming from between the front seats. It sounds a little like a saw or something, but not nearly as loud. I'm guessing it's just a vibration. It's very intermittent and it seems to go away once I'm driving.

Anyway, maybe it's all stuff for me to get used to. Just want to make sure.