My Mazda B4000 4×4 p/u has vibration that seems to come from under driver’s seat. I only notice it at highway speed, though it vibrates to some extent at all speeds. . At 65 mph, it’s tolerable, but at seventy + it shakes the whole truck. If it is vibrating and I let off the gas, the vibration quits immediately, so it can’t be the wheels or tires.

I was told that 4×4 Ford Rangers (same as Mazda) are notorious for problems with the front drive shaft. Something about it spinning even though 4 wheel drive is not engaged.

I have an oil leak coming from the engine, I think. I had the heads replaced in 2008. This oil leak is covering the underbody, making it hard to see if the transfer case is leaking. I’ve tried shaking both drive shafts, and they don’t budge. My tranny oil is black, but hasn’t lost any in two weeks (since I filled it from the ‘low’ mark.) Any ideas?

Is this a driveshaft problem? A transfer case problem? How much should it cost to fix? The truck has over 200,000 miles on it.