M925 making a strange noise

[Olpa77]

Since I have owned my M925 I have noticed a strange jingle/ chatter noise that sounds like it coming from behind and underneath the cab. It does intermittently and only when moving. It seems to do it most when I am running high speeds for a long time, then when I slow for a stop sign you can really hear it. Eventually it goes away only to come back. I have lubed all fittings and inspected the drive line. I can not find any thing loose and all differential oil levels are ok . Can anyone point me in the right direction? I wish I could better describe the noise. I've never heard a vehicle make a noise like this before. It almost sounds like car keys in a pop can spinning.

 

[gimpyrobb]

Have you checked the parking brake assembly? They sound like that when parts are out of adjustment.

 

[Olpa77]

No I have not I'll have to give it a check over.

 

[gimpyrobb]

I bet you will find a broken spring or something out of adjustment. Good luck!

 

[Olpa77]

Finally got around to the parking brake. I disassembled the parking brake on the drive line. Every thing checked out. Adjusted it and it functions like it should. Took it for a test drive and the noise is still there. Seems to do it when coasting or decelerating after running at higher speeds (50- 55Mph) for a while. I put the transmission and transfer case in neutral while coasting when the noise is present and it does not go away. I guess to best describe the noise is like a loose disk chattering or jingle. Only does it intermittently when the truck is in motion and not parked at idle. I still can't find any thing loose on the drive line or braking system, parking and service. I checked the exhaust for loose clamps or mounts and every thing checks out. Not sure what to check next. Maybe just drive it until some thing breaks!

 

[R Racing]

Does it increase and decrease with the engine rpm. Had the fly wheel bolts come loose on a m915 that made a sound that increase with rpm but under load it would quiet down just a bit . But when it would be off of a load it would get a bit louder.

 

[Olpa77]

Does not increase or decrease with rpm. Stays the same.

 

[R Racing]

Than it isn't that thank God !!!

 

[R Racing]

Did u look at the winch control box. There is linkage and springs in there as well.

 

[Mike929]

Can you record a video and post it? This would provide audio of the sound you are hearing.

 

[brasco]

Davit Boom Roller?

I had a similar noise coming from behind me on my M925A2 and it was the spare tire davit boom roller shaking around. I secured it with plastic zip ties and the noise went away.

 

[Olpa77]

Thanks for the idea Mik929. I had the wife record the noise as I was driving it today. Sorry about the picture, she held her phone out the rear window to best capture the odd noise. The First video it starts making the noise about 15 seconds in. Also in the first video I shifted into neutral so you could hear it better.
https://www.youtube.com/watch?v=Pu1CKAHKzf8&feature=youtu.be

https://www.youtube.com/watch?v=8QcD9m-ytlk&feature=youtu.be

 

[Castle Bravo]

Is it one of the axle driveline flange dust caps? I had one loose that sounded like that.

 

[acme66]

My tire davit sounds a bit like that if I don't pull on things with a rubber bungee. Not saying that is it but it sure is an easy thing to test. On mine it was the trolley rattling.

Ken

 

[MuleMac01]

Almost sounds like a loose hose clamp around something metal and rattling around it from the vibrations...


maybe the spear tire crane check for loose bolts and washers wiggling around also...

 

[Olpa77]

When brasco mentioned the spare tire davit roller I thought for sure that's what it was. I duct taped the roller so it can't move and had the wife grab hold of the boom and the noise was still present. I'm sorry I should have posted that info when I posted the video. I am going to remove the spare tire and see if that makes a difference. Can any one point me to the right TM on the dust caps Castle Bravo was referring to? Does anyone think it could be something in the transfer case? For now work is calling me so I maybe gone for a week or two. I am sure I will find the cause of this problem with your help. Thanks so much.

 

[Scott88M]

Sorry I didnt watch the video but I immediayely thought the spare tire trolley thing too since mine made so much racket I put it in the toolbox. MY spare tire also has a chain wrapped around it holding it in place I never knew that until the end of it came loose and was dangling under the truck. Id check if you have that too maybe rattling around.

 

[plode]

Check the bolts for the muffler support bracket. Mine were loose and rattling around.

 

[Rjolson]

I found The platform above the fuel tank will vibrate, might want to look at that, mine looked secure but when I hit it with my fist a couple of times it started to vibrate and make they noise you described.

 

[Olpa77]

Update. I got home from work earlier than expected thanks to the upcoming holiday. Took spare tire boom off and removed the spare. Took it down the road and it still does it. Got it out on the interstate and had my wife follow me. She could hear the noise following me from quite a distance behind me. She passed me on the left and right sides. She said it is extremely loud by the rear axles on the passenger side as if its the rear ends making the noise. The more I drove it the louder it got. Its extremely loud now after driving it 30 miles today. It now does it all the time while the truck is in motion only.