Wth is causing this squeal?

Ok, just got it back up high on jack stands. It's coming from the flex plate. I can put a tube up there to listen. Wth could that be?

Just strange since it comes and goes.
 
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Sounds like metal on metal, can you drop the pan and check the rearmost crank bearing? Or remove the trans and converter and see if it continues. Could be a stuck band on the trans
 
Shreddinlettuce said:
Sounds like metal on metal, can you drop the pan and check the rearmost crank bearing? Or remove the trans and converter and see if it continues. Could be a stuck band on the trans
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All will be a real bitch in this car. I'll remove the starter in the am so I see if anything is visible.

I'll have to pull the whole drivetrain to do anything.
 
Doesn't sound like a vacuum leak. Sounds more like a dry bushing squeal to me. If it's around the flexplate, the only things I can think of are the starter bendix not retracting, the torque converter bushing, the transmission pump, or the converter not being bolted to the flexplate and the converter snout spinning inside the counterbore in the crank.

I'm guessing the transmission has fluid and it's probably a driveable car, but I don't know, so I named off what I could think of.
 
Croatan_Kid said:
Doesn't sound like a vacuum leak. Sounds more like a dry bushing squeal to me. If it's around the flexplate, the only things I can think of are the starter bendix not retracting, the torque converter bushing, the transmission pump, or the converter not being bolted to the flexplate and the converter snout spinning inside the counterbore in the crank.

I'm guessing the transmission has fluid and it's probably a driveable car, but I don't know, so I named off what I could think of.
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Yep, running driving car. Drives and shifts pretty good.

One thing to note. This was an abandoned project i picked up. I did, unknowingly, start it the first time without the converter bolted up. I really thought it was a belt though.
 
justjeepin86 said:
Yep, running driving car. Drives and shifts pretty good.

One thing to note. This was an abandoned project i picked up. I did, unknowingly, start it the first time without the converter bolted up. I really thought it was a belt though.
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That sounds like probable cause for a torque converter bushing
 
I mean...the belt would be my first guess, but as we all see, it's not on in the video.

It sounds almost exactly like cutting an ID bore on something kinda thin walled, on a lathe, with a boring bar. I can't unhear it.

Definitely pull the starter and see if you can see anything inside the bellhousing. Rub marks on the back of the flexplate, any kind of material from the converter touching/rubbing something, or any evidence of the starter hanging up.

Any chance it's on the intake (before the throttle body) side? Probably not since you said it's loudest underneath the car, but I figured I'd ask anyway. Does it only do it at idle?

I'm quite intrigued as to the cause of this noise!
 
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Croatan_Kid said:
I mean...the belt would be my first guess, but as we all see, it's not on in the video.

It sounds almost exactly like cutting an ID bore on something kinda thin walled, on a lathe, with a boring bar. I can't unhear it.

Definitely pull the starter and see if you can see anything inside the bellhousing. Rub marks on the back of the flexplate, any kind of material from the converter touching/rubbing something, or any evidence of the starter hanging up.

Any chance it's on the intake (before the throttle body) side? Probably not since you said it's loudest underneath the car, but I figured I'd ask anyway. Does it only do it at idle?

I'm quite intrigued as to the cause of this noise!
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My first thing was to spray starting fluid all around the intake and tb, before I put the car back up on jack stands.

Completely agree on the sound. Wren I put a tube to my ear and listen, it's definitely from the bellhousing area. I'm pulling the starter after i have breakfast this morning. It's a nightmare with the headers.
 
Ok @Croatan_Kid

I think this came from what I mentioned above. Starting it without the converter bolted to the flex plate. I pulled the trans back today and found a burr with shiny metal on the snout of the converter. I imagine that's where the noise is coming from.

How far should the converter engage the crank? it was barely in. See pic.

20250922_153850.jpg
 
Well, this isn't how I wanted my extra day off this week to go. The plan was for it to be finished other than tidying up wiring. I was driving this thing yesterday morning.

I cleaned up the converter and crank with sand paper the best I could and pulled it back together. Same noise. Now I completely dropped it. We'll see.....

20250922_183642.jpg
 
justjeepin86 said:
How far should the converter engage the crank? it was barely in. See pic.
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Well...more than that. Probably 1/4 to 3/8-ish. Enough so they're engaged, can run concentric, and the crank can help support the weight of the converter.

With the transmission bolted to the motor and the converter slid all the way back in to the pump, there should be a gap between the mount feet and the flexplate. You should be able to slide it forward and have everything mate up fairly flush.

My guess would be that the converter snout won't slide in the back of the crank. Then when they're bolted together and spinning, that's where the noise is coming from.

Best case, you can clean up the converter snout and get them to slide together. Not quite worst case, maybe you need a different converter. Worst case, the crank pocket is fubar.
 
Croatan_Kid said:
Well...more than that. Probably 1/4 to 3/8-ish. Enough so they're engaged, can run concentric, and the crank can help support the weight of the converter.

With the transmission bolted to the motor and the converter slid all the way back in to the pump, there should be a gap between the mount feet and the flexplate. You should be able to slide it forward and have everything mate up fairly flush.

My guess would be that the converter snout won't slide in the back of the crank. Then when they're bolted together and spinning, that's where the noise is coming from.

Best case, you can clean up the converter snout and get them to slide together. Not quite worst case, maybe you need a different converter. Worst case, the crank pocket is fubar.
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It's really weird though. I can slide the converter back and forth in the trans easily. And it slides right up to the flex plate with no gap. I didn't pull it in with the bolts. That's where my confusion lies. I'm thinking pump bushing, like @Shreddinlettuce mentioned.
 
justjeepin86 said:
It's really weird though. I can slide the converter back and forth in the trans easily. And it slides right up to the flex plate with no gap. I didn't pull it in with the bolts. That's where my confusion lies. I'm thinking pump bushing, like @Shreddinlettuce mentioned.
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But is the pilot on the converter sliding in to the crankshaft like it should?

If you would, take a picture of the back of the motor. I'd like to see the flexplate and the crankshaft hub. This way, I can figure out if there's any issue with long crank/short crank alignment. If we eliminate that, then we can diagnose further.

Unless you or the previous owner know what the motor and transmission came out of originally and if they were a mated pair.
 
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I added some more stuff to my previous post.
 
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