What in the ROCKS? 3rd Gen noise

[hoksibish]

So my 3rd gen sounds like a rock is rattling around in the bell-housing. However it only rattles when the truck in gear. Park and neutral the sound goes away. The noise also takes a bit to start after a cold start. I took a stethoscope and poked around and cannot find the noise anywhere! The newest thing is now when the motor stops it sounds like the rock is still rattling around for a couple seconds. This doesn't sound consistent like a flex plate crack but maybe??

Thought I would reach out to see if anyone has heard this before.

Link to a video.

 

[BrianK14]

Sounds like it could be the cat heat shields. Bang on them a bit, you’ll quickly know if that’s the source of your noise

 

[shadow247]

Check the heat shields on the exhaust. There is a small one that is barely spot welded on, and another that is held on by 2 bolts. 1 bolt was missing, and the welded one fell off when I touched it.

 

[hoksibish]

thank you for the suggestions. Just checked and the exhaust is solid. No missing nuts or bolts. Started the truck and it was quite till it warmed up and I put it in drive and reverse. That's the only time the noise appears.

 

[jgue467]

Check the dampner behind the center diff (metal plate w/chunk of rubber attached), it can get loose and rattle at idle or other times. Luck and enjoy the runner. :cowboy:

 

[hoksibish]

Checked the dampener as well. Thanks for the suggestions. I can't seem to find it anywhere. The fact that it only makes the rattle when the truck is in a gear, torque converter maybe?

 

[nc-grayson]

Have someone sitting in the drivers seat mashing the brake with e brake on and in gear, narrow down location

 

[sandracer33]

That's how mine sounded when the flexplate started to fail. I chased every heat shield, bracket and clamp on the truck. Even looked at the drive belt idler bearings & a/c clutch. Got progressively worse over 3 months until I was able to confirm what it was.

Sent from my Pixel 3 XL using Tapatalk

 

[repo]

There is a black cover you can remove on the front of the bellhousing and look inside (with a mirror, super awkward). The flex plate is somewhat open to the enviroment so you could actually have a small pebble rattling around in there. I replaced the cover's gasket thing on mine a while ago which had disintgrated, the bellhousing was full of crud.

Or the flex plate could be cracked. I just replaced mine as PM not too long ago while the transmission was pulled to do the torque converter seal. Did the rear main seal as PM too. Wasn't cheap the flex plate is about $300. You should do the rear main seal, transfer shifter seat and starter contacts/plunger as PM while the transmission is pulled.

 

[hoksibish]

So I pulled the inspection plate. It's very hard to see. If it was cracked at all I should be able to see something right? Most interwebs pictures of a cracked one has the cracks towards the center.

 

[sandracer33]

So I pulled the inspection plate. It's very hard to see. If it was cracked at all I should be able to see something right? Most interwebs pictures of a cracked one has the cracks towards the center.

I couldn't see the cracks on mine until it was almost totally broken in two pieces. It broke the morning I was going to replace it in the driveway at home.

 

[hoksibish]

I couldn't see the cracks on mine until it was almost totally broken in two pieces. It broke the morning I was going to replace it in the driveway at home.

Thats lucky. Thanks for the pointers. Looks like i will pull the tranny and go from there.

thanks again all

 

[hoksibish]

So it turns out it was the TC giving up to ghost. replaced the tc and the rock tumbler is no more.