Weird idle noise, sounds like marbles. Please read.

[scurfman]

I have a 98' 4x4 automatic with the 4.0 ohv. I just turned 100,000 miles and am noticing a noise that seems to be getting proggresively worse. It is not real loud but is definately noticable. It sounds kind of like marbles rattling around. Not really a knock or squeal. I really can only hear it at an idle and can't tell if it it is affected by rpms. I does not get louder. I also know that when I put it into gear it significantly quiets and you can barely hear it. I had the transmission rebuilt at 75,000 because my reverse band broke. I have also used mobil 1 synthetic since 30,000. Last oil change I tried a oil cleaner and added a quart of Lucas thinking it might be my timing chain tensioner, but did not help at all and possibly got a little worse. My oil pressure has always been good. The truck runs awesome and am trying to avoid a rebuild. Any ideas or suggestions I could try. It sounds like it is coming from the back of the motor and is louder under the truck. Does this sound like it could be the transmission or does it sound like motor noise? Thanks for your help.

 

[SoLongStang9499]

From my experience, it sounds like something in your transmission. My mustang used to have a similar noise in park, but once in drive it never made the noise, try that and see if the noise goes away, then you know its in your transmission, if it doesnt be a little bit more specific with its location and when it occurs.

 

[Big Jim M]

You are describing a catalitic convertor or muffler noise quite well.. Get under there and use a rod touching them and see if the noise IS coming from one or the other of them..
Big Jim

 

[scurfman]

Thanks for the quick response. I will try that and let you know. Feel free to keep posting. Thanks Guys.

 

[SoLongStang9499]

Jim raises a good point, it could be a crack in your cat, and could be bouncing around in there making noise.

 

[scurfman]

Hey guys, I checked this morning using my trusty wood stick stethascope. the noise does not sound like it is coming from my cats. It definately seems like an internal sound. I have stuck the wood on everything I can see and can,t get the sound through the wood.

 

[Big Jim M]

Wood??

Hey guys, I checked this morning using my trusty wood stick stethascope. the noise does not sound like it is coming from my cats. It definately seems like an internal sound. I have stuck the wood on everything I can see and can,t get the sound through the wood.

I never have used wood..Does it work as well as a bfscrewdriver? Have you used the stethascope on various parts of the engine while running? NEVER do this while wearing loose clothing..
Big JIm

 

[scurfman]

Wood works great, try it next time. You can hear the bearings and everything.

 

[289-tiger-]

Don't know if this information will help or is pertinent to your transmission noise but here it is. I have a 05 explorer similar noise, rattling clacking from the bellhousing area (just like a TCC problem). Comes and goes but only occurs after pressurewashing the underside of the vehicle. Will go away after the the vehicle dries. No performance issues. Have noticed the noise will begin when the brakes are applied slowing down almost to stop and will continue until the transmission is put in neutral or acceleration begins. A friend has the similar noise in his Ford. We are looking at the brake relay (a clear shot for the pressure washer) at the master cylinder as a possible culprit but have not proven this as of yet. (wood does work)

Good luck

 

[Todd~Rod]

Throw out bearing?????

 

[scurfman]

It is an automatic. similar sound though.

 

[superranger4.0]

loose tourqe convertor bolts, cracked flex plate

 

[truckingixxer]

i think its piston slap I have the same noise, I put my head by the bottom of the door and it sounds kind of nasty but its been doing it for a while and my truck runs great, this is what others have told me from rangerpowersports.com

 

[427ford]

If you end up tracing it to under the hood.. try removing the serpantine belt and then spin all the accessories and pulleys. I've had idler and tensioner pulleys get noisy on Fords, when the sealed bearings are failing. Check the fan clutch and water pump for rough bearings / lateral movement. If there's knocking IN your cat converter, it's time to replace it.