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-   -   Mystery noise when in drive. Video.. (https://67-72chevytrucks.com/vboard/showthread.php?t=447433)

eightbanger 02-17-2011 11:53 AM

Mystery noise when in drive. Video..
 
This only starts to happen after the Truck has warmed up, the sound is only heard when i'm stopped at a set of lights with my foot on the brake and in drive, when I put it in Neutral it goes.....just like it shows in the Video.
Any ideas of what this might be are greatly appreciated.

Edit: seems to be coming from the Stall Converter/FlexPlate area

http://i33.photobucket.com/albums/d7...rannynoise.jpg

geezer#99 02-17-2011 03:08 PM

Re: Mystery noise when in drive. Video..
 
Your youtube link is the wrong one!!!

bruceman1968 02-17-2011 03:14 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by geezer#99 (Post 4493175)
Your youtube link is the wrong one!!!

Geezer#99 click on the picture and it will go to his photobucket link..I heard what he is talking about but I have no idea what it is.........

eightbanger 02-17-2011 03:26 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by geezer#99 (Post 4493175)
Your youtube link is the wrong one!!!

Yeah, just move your mouse over the image click it and it plays in Photobucket.

geezer#99 02-17-2011 03:50 PM

Re: Mystery noise when in drive. Video..
 
Sorry. Clueless Old guy!!
Sounds like a cracked flex plate.

eightbanger 02-17-2011 04:07 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by geezer#99 (Post 4493228)
Sorry. Clueless Old guy!!
Sounds like a cracked flex plate.

Wow! I hope not, that things only a about 18 mths old, I'm gonna check it though since it's the thing I would have least expected to have happened but would turn out to be the most lightly...if that makes sense.:lol:

Thanks geezer.

68gmsee 02-17-2011 05:59 PM

Re: Mystery noise when in drive. Video..
 
Couldn't hear the noise you refer to for all the noise from the engine.

Try my garden hose stethoscope trick to isolate. Take a 2 foot section of garden hose and place it near or on the suspected area and the other end to the ear and see if you can make out where the noise is the loudest.

Brainchild 02-17-2011 06:14 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by geezer#99 (Post 4493228)
Sounds like a cracked flex plate.

That's my guess, maybe the converter is loose

HulkSmash 02-17-2011 06:55 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by geezer#99 (Post 4493228)
Sorry. Clueless Old guy!!
Sounds like a cracked flex plate.

Quote:

Originally Posted by Brainchild (Post 4493502)
That's my guess, maybe the converter is loose

I'd put money on one of these two, but i'm leaning twards the cracked flex plate. The vehicles I've experienced with loose converter bolts seemed to make sound all the time.

But I hope it's just loose bolts.

Jeffs70 02-17-2011 07:07 PM

Re: Mystery noise when in drive. Video..
 
if you watch the video the converter is moving back and forth and wobbly quit a bit. looks to me as if its loose from the flex plate.

eightbanger 02-17-2011 07:30 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by 68gmsee (Post 4493475)
Couldn't hear the noise you refer to for all the noise from the engine.

Can't believe you can't hear it 68, the noise starts as soon as I drop it in gear at about 11 seconds in then stops at 20 sec when I put it in Neutral.

Thanks guys, gonna get under it tomorrow and have a close look at that FP.

68gmsee 02-17-2011 07:57 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by eightbanger (Post 4493624)
Can't believe you can't hear it 68, the noise starts as soon as I drop it in gear at about 11 seconds in then stops at 20 sec when I put it in Neutral.....

I guess I should have said "can't differentiate." Are you referring to the hollow sound that sounds like knocking on a hollow log?

I'll listen to it a couple of more times but with all of the engine clatter, exhaust rumble I wasn't sure if it was the mike on your camera or the engine.

matthew20061 02-17-2011 08:06 PM

Re: Mystery noise when in drive. Video..
 
I can hear it, sounds like a rubbing sounds of some sort. I would try and make sure the converter bolts are tight first and if that doesn't fix it I'm not really sure what would cause that.

68gmsee 02-17-2011 08:09 PM

Re: Mystery noise when in drive. Video..
 
Okay, I'll take a guess and say it's related to something in the tranny also. I'll say torgue converter.

I've worked on machinery of all kinds for the last 50 years or so and one thing I do when trying to isolate a noise is to listen for oscillation of the sound in relation to the revolution of moving parts. As an example if the sound oscillation were to coincide with the rotation of an alternator pulley I would guess the alt bearing as the culprit.

Your's may be a little harder to isolate. If the hose trick indicates it's coming from the tranny, then you gotta bite the bullet. :(

y5mgisi 02-17-2011 08:11 PM

Re: Mystery noise when in drive. Video..
 
Curious to see what you find. Mine is making a similar noise.

eightbanger 02-17-2011 08:20 PM

Re: Mystery noise when in drive. Video..
 
I absolutely hate fiddly ass cr*p like this, odd little knocks and clanks and giga giga giga noises like this one they suddenly appear and take ages to locate or identify. I'll try the hose trick 68 and i'll let you all know what I find, if I can find it that is....

trevrolet65 02-17-2011 08:27 PM

Re: Mystery noise when in drive. Video..
 
I hear a ticking noise. Are those the right length bolts on torque converter and are they tight? Had a square body do that and tightend bolts on verter and month later did it again. New bolts fixed it, had to be from trans shop problem. Just a thought.

biggestjohn 02-18-2011 06:02 PM

Re: Mystery noise when in drive. Video..
 
If its something in that "stall converter", its going to be a pain to diagnose, but thats where my guess is. Sounds like it has a bearing or something failing. When it is sitting stationary, with a load it is making it chirp, but when in motion, the load is reduced. When I listen to the video when in neutral, I hear a slight chirping, which then gets worse when load is applied.

Heres another hint, you say it only does it when its warmed up. Torque converters work by hydrolic coupling of the vanes, but when the tranny fluid gets warm, it also gets thinner, thus allowing more slip.

Can you put a stethescope on the bell housing?

If you hold the brake with it in gear and rev the engine a little, does it get worse?

eightbanger 02-18-2011 07:04 PM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by biggestjohn (Post 4495718)
If its something in that "stall converter", its going to be a pain to diagnose, but thats where my guess is. Sounds like it has a bearing or something failing. When it is sitting stationary, with a load it is making it chirp, but when in motion, the load is reduced. When I listen to the video when in neutral, I hear a slight chirping, which then gets worse when load is applied.

Heres another hint, you say it only does it when its warmed up. Torque converters work by hydrolic coupling of the vanes, but when the tranny fluid gets warm, it also gets thinner, thus allowing more slip.

Can you put a stethescope on the bell housing?

If you hold the brake with it in gear and rev the engine a little, does it get worse?


Had a thorough look at it today, no cracks on the FP and nothing was loose I did re-torque of the bolts on the FP just incase, checked to see if the noise was coming from the Trans, and it's not. So I topped it up with trans fluid and it's still making the noise.

I'll try what you suggested biggestjohn, revving a little while in gear and report back.

BBrendal 02-19-2011 12:20 AM

Re: Mystery noise when in drive. Video..
 
With the converter unbolted and pushed all the way in the pump of the trans you do not want to have more then 3/16 of space between the flex plate and the converter. If you do put a washer (all 3 equal thickness) between the flexplate and conveter on all 3 converter bolts to make the distance less then 3/16 of an inch. I use a drill bit. Put all 3 in loose then go around again and snug them tight. You dont want to be too snug between the flex plate and converter though either so dont go too thick on the washers. If the converter spins (with no bolts in it) and it is under 3/16 you are good. It sounds like a cracked flexplate to me as well. Ive had some you cannot see any cracks but they have a small fracture in them mostly from improper tightening with too much of a gap between the flexplate and the converter.

Spoof 02-19-2011 12:30 AM

Re: Mystery noise when in drive. Video..
 
My new engine and new TH350 makes the same sound on occasion, coupled with the odd squealing noise.
My mechanic thought it was the starter not disengaging fully, which I doubted. He greased the whatchamacallit and it briefly went away. Still a mystery for me too.

Longhorn Man 02-20-2011 10:21 AM

Re: Mystery noise when in drive. Video..
 
i doubt it is in the converter/flexplate. I suspect it is in the trans.

Hart_Rod 02-20-2011 10:31 AM

Re: Mystery noise when in drive. Video..
 
I'm confused (not uncommon, :)). Does it make the noise in neutral but not in any other gear position or drive and not any other gear position?

Fldawg 02-20-2011 10:36 AM

Re: Mystery noise when in drive. Video..
 
Had a truck the other day at my shop making the same noise when you put it in gear and it was a cracked flex plate, maybe yours is the same thing .

eightbanger 02-20-2011 11:01 AM

Re: Mystery noise when in drive. Video..
 
Quote:

Originally Posted by Hart_Rod (Post 4499301)
I'm confused (not uncommon, :)). Does it make the noise in neutral but not in any other gear position or drive and not any other gear position?

Only makes this noise in drive and reverse, but quiet in neutral, tried revving a little when in drive with my foot on the brake and the noise sped up.

I am pissed as the Trans was overhauled and the FP & Stall were replaced all at the same time not that long ago.


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