Nasty Rattle

[crash-harris]

So the other day I fixed a terrible burnt up patch job on the exhaust. A PO had used a thin piece of pipe and buggered welds to seal between the factory 3" pipe and the 3" ID to 4" adapter. They did this with a 3" OD coupler and a piece of 3" OD pipe in the adapter. I simply replaced the hole clusterf*** with a 3" ID to 3" OD pipe. This was done at the back of the cab, just before I left for work.

Once in the parking lot at work, about 18 miles away, I heard a terrible rattle from under the truck at idle (waiting for a parking spot). Sounded like a loose exhaust clamp or chunk of plate steel. Once parked I crawled underneath with the truck idling and it sounds more like it's coming from the bellhousing. Can't hear it from under the hood, in cab with all windows up, or in the bed. I have no inspection shield on the transmission. I did check the DMF again once I shut the truck off and there is still only about 1" of play or less in it and all springs and seats I could see were in place. Sound doesn't go away when I depress the clutch pedal, but will go away as soon as I start to move. Double checked and rechecked ALL exhaust clamps and they are TIGHT.

Ideas?

 

[crash-harris]

And just found that increasing engine speed from 750 rpm to 800 rpm with the accelerator doesn't make it go away, but does make it less noticeable. At 800 rpm, not moving (unloaded), it sounds more like there is something laying in between the two parts of the DMF and rolling around, about like when something comes loose in a drum brake and bounces around while the drum is spinning.

Could this be parts of the DMF hub falling out inside the DMF?

 

[79jasper]

Dmf. 1 inch is a lot of play.

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[crash-harris]

I know, I learned all about that in my "how long will it last" thread. It only barely clinked while idling less than a month ago and it would go away when pressing the clutch pedal.

 

[79jasper]

I guess I'm just not sure what your question was then.

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[crash-harris]

Wondering if anyone else has experienced this as part of progressive DMF failure, or as anything else really.

 

[79jasper]

Oh, my brothers truck did that.
Actually some of the springs had come out and we're laying in the dust cover.

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[crash-harris]

Guess I'm going to have to mark the springs. Everytime I check them, every slot that is visible has the springs and seats all in place.

 

[79jasper]

But they could be broke off inside.

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[lotzagoodstuff]

Listen to Jasper: an inch is way too much movement in a DMF. If you are low on cash think about trying the Lucky Mod.

Good luck

 

[crash-harris]

Not low on cash, just time. I didn't realize there were springs deeper inside. That's what I was looking for. Another one probably went then. I'll hopefully be ordering my Luk SMF and clutch this month. I'll have to wait until about next month to take it to the shop down the road. I'm not excited about someone else doing the work, but I just don't have the time.

 

[79jasper]

Few hour job with a trans jack and a buddy.

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[crash-harris]

All things I don't have at the moment, or anything that a jack will roll on. I do 2nd shift at building KW's and doing anything physical before I go to work means that you run out steam halfway through the shift. And the assembly line doesn't stop or slow down

I could do it on a weekend, but those are full with fence building until it's done, then they'll be full of working on the Bronco until is done. I'd be looking at not being able to do it myself until October at the earliest and I'm not sure the DMF will make it that long.

 

[riotwarrior]

Have a gander here...this might help you visjalize whattf is happening
https://youtu.be/KJRCV5_LTuY

 

[crash-harris]

That helped a lot, thank you! Mine is doing exactly what you are describing in your video. Springs and seats are all in place, but it just moves back and forth pretty easy.

So I still don't know what could be causing this sound then, unless a tiny piece of spring broke off, but not enough to deform the spring or let it fall out