Main knock, Piston slap, or Torque Converter?

[y5mgisi]

Or something else? I made this little video trying to diagnose the surge issue on my 90. But lately its been developing a hard core knock at below idle rpm and at start up. You can here it in this video right at the beginning and a couple more times when it surges. I wouldn't recommend watching past the very beginning. Pretty boring. But here you go.

 

[y5mgisi]

To clearify, at 4 sec i drop it into drive, at 5sec it "knocks". so the first batch of clicks you here is me shifting, and the second batch is knocks.

Happens again at,

1:20
1:25
1:56
2:01

 

[DokWatson]

Gotta be something else. You would know if it was knocking. A knock would sound like a couple cracked out midgets beating the crap out of the inside of the engine. They are usually constant noises, not intermittent like yours is. Weird

http://www.youtube.com/watch?v=DfJIpiQZtR4

 

[Big Ray]

I had a loose converter, it was constant and rpm sensitive...

Those other knocks, were you shifting it or did they just happen?

 

[GreenieK30]

Check the flexplate for cracks.

 

[mcwright]

Do you still have the catalytic converter? I had the honeycomb break up in mine once and rattled around inside like a knock. I had a power surge and my engine died. When I started it again the sound was gone. The broken pieces can get lodged in the wrong place and restrict flow. Just an idea.

 

[y5mgisi]

Those other knocks, were you shifting it or did they just happen?

Not 100% sure which knocks your talking about. But i do take it from park to drive and back a few times in the vid. So probably shifting.

Check the flexplate for cracks.

Good idea. Should have done that already! Silly me...

Do you still have the catalytic converter? I

I do, but its a new Magnaflow unit. Its a pretty hellatious knock. Definitely not just a light rattle or even a rod knock.

 

[y5mgisi]

Oh my, When it does it, it actually does sound a lot like this!

 

[diesel4me]

End play in the crank??..I cant listen with my computer--just a guess..try pulling in and out on the balancer,see how far the crank moves..

 

[shady]

I had a loose converter, it was constant and rpm sensitive...

Those other knocks, were you shifting it or did they just happen?

I had this once too. my camaro had loose torque converter bolts and it would knock when Idleing or when you let off but never underpower. did it on startup too. I tightened em up and it went away. took forever to figure it out though, and then it was found by accident while looking for loose tranny to block bolts.

 

[Big Ray]

To clearify, at 4 sec i drop it into drive, at 5sec it "knocks". so the first batch of clicks you here is me shifting, and the second batch is knocks.

Happens again at,

1:20
1:25
1:56
2:01

I meant these other knocks...if it's only happening when you shift, I'm thinking u-joints...of course, that's more clunk than knock...

 

[y5mgisi]

the ones at 1:20 and 1:25 and such are all just sitting there in gear. Motor surging. It just seems to be that the motor drops below "actual idle" for just a sec when i put it in gear and thats what is causing the knock at that point. The other knocks happen when the motor surges and drops back down below idle.

 

[y5mgisi]

I'll check the converter bolts and try checking the flex plate bolts. Also check end play just for fun as well.

 

[dabomb6608]

I have a knock as well. It happens just at startup and on cold mornings it will do it for a few seconds after startup.

 

[diesel4me]

If it sounds like Woody Woodpecker for about 3-4 seconds,thats a loose bearing,rods or mains,that pump up when oil pressure finally gets to them and silences the knocking...

I've had several engines that did that for years with no issues,and a few that blew shortly after the knocking started..mightwant to start saving pennies for a set of bearings ,or maybe a crank kit--eventually the knock wont go away and the engine might just toss a rod if you ignore it long enough..

 

[wasted wages]

The knock in the video is really strange..I've never heard an engine sit there idling and just throw out such a loud knock for just a second or two.....

I would invest in a mechanics stethoscope and listen to different points under the truck with it idling....I sure you can narrow down where it is coming from...

pulling the torque convertor cover and taking a good look at the flywheel and end play of the crank would be where I would start as mentioned before..

Keep us posted....would really like to know what the root cause turns out to be...

 

[kdoske]

I was just going to say the same thing. Have your girl/wife/friend hop in put it in and out of drive while you are under there to see if you can see anything happen when the noise starts. Like said above remove the dust cover and then if its not there start scoping around in the engine with something like this.

 

[y5mgisi]

Will do. I got a friends car in the garage and not a lot of time this week. Next week i will get to it and let you know if i find anything. Thanks for all the suggestions!

 

[Fordum]

Have your girl/wife/friend hop in put it in and out of drive while you are under there

Dude, before you do this, buy her flowers, rub her feet, take out the trash, whatever, just MAKE SURE you are on her good side..........

Oh, and adjust the brakes...


I'm voting for flexplate. Either cracked or loose bolts.

 

[y5mgisi]

dude, before you do this, buy her flowers, rub her feet, take out the trash, whatever, just make sure you are on her good side..........

Oh, and adjust the brakes...


I'm voting for flexplate. Either cracked or loose bolts.

haha!!!!