4spd trans linkage help needed

Is it a "tinney" type knocking or deeper sound? Its hard to diagnose without seeing/hearing it. I would check for things hitting the frame t-bars etc. Remember if it occurs under acceleration your engine and trans or moving around. The drivers side engine mount will try and stretch/lift. and the passengers side will compress. Check for a broken driver's side mount or the trans mount could be bad too.

Other things to do would be to remove the tin plates on the bellhousing to see if the problem goes away.

Another thing to check would be the end play in your crankshaft. You can probably use a dial indicator on the flywhell and move the crankshaft back and forth with a screw driver. I can remember the spec but I think if you have more than .010" this may be your problem. I had a BrandX truck that the center thrust bearing (on the enigne) had worn so bad that when you pushed the clutch in the counterweight would rub the inside web of the block making a knocking sound (opposite to your problem).

I am glad I was able to help with the linkage issue.