Tapping noise
 

I have a 1987 Toyota 4x4 truck that started making a tapping noise. The noise is only there it when its in gear and accelerating. If its in gear but coasting it does not make the noise. it does not make the noise at idle and It does not make the noise in 4th gear, but does occur in all other gears. I spoke with my mechanic and he thinks the problem is in the transmission (its hard to pinpoint the location while driving) since it doesn't do it in 4th gear. maybe a broken gear. He feels that if it was a valve/rocker/rod issue it would do it in all gears. I'm hoping someone here has some ideas before I start exploratory work on the truck to determine the problem. All the fluid levels are good and the motor was rebuild approximately 50,000 miles ago. it does not have any loss in power.

I'm with your mechanic on this. 4th gear is the transmission's 1:1 drive ratio, where the input and output shafts rotate at the same speed, so it's of note that there's no ticking in that gear. And neutral of course separates the engine's rotating mass from the transmission entirely.

I might've suspected you had an engine problem that only had ticking while under load, but a quiet 4th gear rules that out if you hear the noise in 3rd and 5th gears. I haven't needed to tear into a w56 yet, so I'm not educated enough yet to guess what the problem is, but I'd bet your engine is safe.

Depending on where you live, it might be easy to find a used replacement. Even up in NE Ohio, it's under and hour's drive to pick up a w56.