My engine (or whole truck) seems to shake when I shift into second gear and accelerate under load. This only happens around 2000-2500 RPM and when Iam leaving a stop light or coming out of a tight turn that brings my truck down around those RPM's. Its kind of hard to explain but it is kind of like a "quiver" then goes away. Again, it is only in second gear. Every other gear feels perfectly smoothe. My truck has 151,xxx miles on it and the clutch seems to be fine (just had it checked out). Any suggestions would be helpful.