54 1/2 ton with saginaw 4 speed. I'm getting a very loud and strange growling noise when I depress the clutch. Doesn't always do it and usually in first or reverse gear.It's intermittent. I thought it was the throwout bearing so I changed that and still have the problem. I'm wondering about thr pilot bushing. It almost seems like maybe it's spinning in the crank at times. Is it supposed to not turn in the crank but the input shaft turns inside the bronze bushing? Could that be making my noise? Anybody have a problem like this before with a pilot bushing?-----thanks