69 Conti 4dr 460, stock 2.80 open diff, pretty sure lincoln only.
Getting a clanking banging noise, rhythmic. Sometimes sound, GENERALLY on deceleration off throttle coasting down hill. Speed seems to affect it as far as speed of the bang. When noise starts if it accelerated even slightly goes away. but i have had it happen on the flat just cruise control on. I have had it at high speeds and 20mph. it is much louder when riding in back seat. I cant make it happen at will. Some drives it wont happen, some drives it happens often, even replicating same route and speeds. i dont seem to have any control over the noise except accelerating to go away.
I have tried putting it in 2nd and going up and down hills to see if i can force the sound, it never happened during that test. I have NOT been fast enough on the draw to slide into neutral and roll while it happens to see if that changes it.
I have put it up in air on jack stands and spent a long time looking and shaking bits for looseness but nothing I could find. the rear end I believe to be original and untouched, so 51years 103xxx miles. Pulled the fill plug and it was full. Drive shaft was professionally rebuilt (new U joints all around) and balanced. But that was 12 years ago but only 15xxx miles. These are (I think and i might have the term wrong) double cardone joints on each end? I think meaning move pivot points than usual for smoother running.
i suppose something else could be rattling but it all seems rigid and not contacting each other. My thinking, though i dont want to influence your thinking, maybe rear center? lash issue? wear issue? coming on the coast side of ring and binding? accelerate to get on the thrust side goes away? but if doing that shouldn't I be able to make that happen pretty easy? and regardless of gear the trans is in? and i was trying to load and unload the diff in one of my tests and it never did it? Like if diff related shouldnt it be an all the time thing not a come and go thing? even if it requires specific circumstances, if i do those things it should happen, but so far not the case.
open to suggestions? Trying to find a place to bring it to local, hard to find anyone I trust and dont often farm stuff out. but im dumbfounded.
Getting a clanking banging noise, rhythmic. Sometimes sound, GENERALLY on deceleration off throttle coasting down hill. Speed seems to affect it as far as speed of the bang. When noise starts if it accelerated even slightly goes away. but i have had it happen on the flat just cruise control on. I have had it at high speeds and 20mph. it is much louder when riding in back seat. I cant make it happen at will. Some drives it wont happen, some drives it happens often, even replicating same route and speeds. i dont seem to have any control over the noise except accelerating to go away.
I have tried putting it in 2nd and going up and down hills to see if i can force the sound, it never happened during that test. I have NOT been fast enough on the draw to slide into neutral and roll while it happens to see if that changes it.
I have put it up in air on jack stands and spent a long time looking and shaking bits for looseness but nothing I could find. the rear end I believe to be original and untouched, so 51years 103xxx miles. Pulled the fill plug and it was full. Drive shaft was professionally rebuilt (new U joints all around) and balanced. But that was 12 years ago but only 15xxx miles. These are (I think and i might have the term wrong) double cardone joints on each end? I think meaning move pivot points than usual for smoother running.
i suppose something else could be rattling but it all seems rigid and not contacting each other. My thinking, though i dont want to influence your thinking, maybe rear center? lash issue? wear issue? coming on the coast side of ring and binding? accelerate to get on the thrust side goes away? but if doing that shouldn't I be able to make that happen pretty easy? and regardless of gear the trans is in? and i was trying to load and unload the diff in one of my tests and it never did it? Like if diff related shouldnt it be an all the time thing not a come and go thing? even if it requires specific circumstances, if i do those things it should happen, but so far not the case.
open to suggestions? Trying to find a place to bring it to local, hard to find anyone I trust and dont often farm stuff out. but im dumbfounded.