I'm trying to narrow down a noise and need some input in helping distinguish whats what...

With a mechanics stethescope, I can run it along the engine oil pan, and its relatively mute, then starts quite strongly at the transmission bellhousing, and the further back you go on the transmission it quiets down. One tranny shop I took it to put it on the lift and had the same thoughts - says its something between engine and tranny, probably cracked flexplate. Second tranny shop didn't have time to get it on the rack, but from what he observed by ear thinks it isn't in the tranny but believes its a flexplate - said front pump makes a different noise, and if it was the torque converter it would be significantly louder.

So I get under the car, and I can see the engine side of the flexplate, no observable cracks. You'd figure if it was a busted flexplate, it would crack all the way through, especially if its making a racket as loud as it is.

My dilemma is, I hear the same noise with the stethescope in the alternator and in the starter, but not anywhere in between on the block. I replaced starter with spare and took off belt, made no difference in the vibration echos. How do I know the noise I and everyone else hears in the transmission isn't another echo?

Another fyi - earlier on I believed it was something in the engine oil pan so I took it off - nothing observable, crank far from the pickup, no shiny parts on the pan. I don't want to take it back to the engine rebuilder unless I know for sure its not the tranny - I may have to find a manual bellhousing and flywheel so I can start the engine w/o any attached tranny. But, when the pan was off and engine running, the noise was significantly quieter (I held up a shallow container of oil to the pickup and ran it for a couple seconds).

I used to routinely break stock flexplates in my worktruck. (eventually fixed with SFI certified plate)....the noise from a small crack is quite amazing....sounds like a rod is hammering. If you are going to the trouble of pulling the trans,,,why not pull the plate and have a look.

PS: Loose flexplate bolts can slot the holes....almost undetectable without removal.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Well... dropped tranny today. Flexplate is solid, nothing evident after quick glance. Face of converter looks ok. Decided I wanted to drain converter too... slid it off and ....



Uhoh! Broken piece stayed in tranny. How on earth did that happen? Torque converter was seated fully, I did pull it up to meet flexplate.

You think tranny needs full disassembly/rebuild due to metal particles? I may be able to remove seal and pull out the chunk, didn't look into that yet.

I had that happen on a Stock 1975 Dart Sport /6 once...I ended up swapping in a full assembly (TC and 904) from a 1976 Volare....worked ok until I sold the car...


Not sure why the nose failed like that either,

-D.Idiot

I imagine the bushing in the front pump got torn up pretty good. I seem to remember hearing that splitting the pump drive isn't a terribly uncommon failure in the TF transmissions and their derivatives.

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Used to own:
'82 Dodge D150
Erson 270 Cam, O/S valves, mild port work, ~9.5:1 compression

Currently fighting with an '85 VW Cabriolet

My other passion