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Help Needed ID'ing This Sound

800 Views 17 Replies 9 Participants Last post by  Epartsman
Hello all.

Thank you for taking time to read.

So my 2000 Astro AWD started making this noise upon cold start. After a few minutes it will get a bit better. Everything seems to be in order but obviously something is off. Most recent work done was to replace the alternator and the battery. I can't seem to find a connection between the repair and the noise.

Note that I have been getting P0420 DTCs and had not yet gotten a chance to investigate since this appeared.

I've done a little reading and I'm not sure if this could be the worn distributor, or, something much worse. I believe that the disty is original and I'm approaching 300k miles. I'm hoping you'll recognize this noise which will help me find it and fix it. Budget is very tight and we're already down one vehicle.

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Okay! Lots of good info. Thank you so much!

To answer some questions.

It is about due for an oil change. Probably 4k on this last change. The strange part is that it had been sipping oil .. about two quarts over a change (3-5k) and now it has stopped. That also has me concerned (crazy saying that you're worried when your engine does not use oil...). I believe the oil loss was due to external leaks though, valve cover gaskets, etc. most everything has a nice coating of oil underneath.

I did replace the disty cap and rotor, the wires and sparkplugs this summer. I think the plugs I pulled out were original. I know, they shouldn't have run that long, but after going through the replacement process, my concerns about the near impossibility of changing the driver's side plugs was confirmed. Some Engineers should be shot!

I will look into the shroud. Maybe something is a misaligned. I thought I would have recognized that sound.

Would this symptom come on suddenly? It just started happening within the last couple of days it seems mostly due to the colder weather. Before that, nothing hinting at a problem even after the alternator change. This sort of goes with the rod theory.

Thanks for the clarification on the P0420.

We did have a no-start situation happen about 10 days ago.. it was one of those humid days / light rain.. sometimes it doesn't start in those conditions right away. I was suspecting the coil needed replacing but had not yet gotten to it.. dogbox and all..

Wouldn't a worn disty gear cause misfires too? Maybe the gear finally gave up? I'm pretty nervous about checking that because I'm afraid I won't get it back in in time once I pull it out.

Thanks for the video link.

I'll report back with more info.
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Just a quick update.

So I was finally able to get underneath and check things out. The noise got worse then changed character, sorry no recording of that since I shut down the engine immediately.

After driving it (before the noise change) I noted that it seemed to be a different noise if I was in reverse versus a forward gear.

This lead me to thinking about a broken flex-plate.

With hopes that it was the flex-plate I pulled the inspection port on the transmission bell-housing. After getting my head around what I thought I was seeing, I think that at least the flex-plate / torque converter area is suspect. I can spin the torque converter freely with my fingers through the inspection port.

Obviously, this isn't how things are supposed to work... I have no idea where the bolts are that hold the two parts together. Presumably they are somewhere in the bell housing. The one really odd thing is that there is a rubber plug near the inspection port. It sort of looks like a rubber hose hanging out the bottom of the joint between the bell-housing and the block. The internal end of that plug is wedged in between the flex-plate and the block and the bell-housing. I've not yet developed a theory on how that happened...

So, once I get things apart I'm going to run the engine just to make sure I don't also have an engine issue.

Time to go do a lot of reading on how to pull the trans out with common tools and on the ground.. or sitting on jack stands.

I will report back here with either a link to my saga in the transmission forum, or with more info about any engine noises..

Thank you all for your ears and suggestions.

More to follow...
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Well, since you asked for photos.. at the risk of running this thread completely off topic for the forum.. here are the discovery photos. Not the best, but it illustrates what I currently see...

Flex plate and converter where a bolt should be installed.. Note some small metal shards (out of focus)..

Liquid Fluid Wood Tints and shades Fish

The rubber plug jammed between the bell housing and the flex plate ..

Automotive tire Tints and shades Metal Automotive wheel system Electric blue

Shot showing the flex plate bolts.. and from this angle the flex plate does not appear to be fractured.

Automotive lighting Hood Car Vehicle Motor vehicle

I've spent the better part of a day reading through the relevant posts in the transmission section. The folks you mentioned appeared there often.

I'll probably start a thread in the transmission forum and put a link here..

I wonder what fun awaits...
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A link over to the Transmissions / Automatic thread where I've posted my questions and some photos of the aftermath.

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