Low RPM speed noise.

[Pontisteve]

BrooklynBay,

I have an 03 EB Explorer 4.6 4wd. The thing has made a strange noise since I bought it at 80k until now at 115k. Never gets better or worse. It sounds like it has a loose catalytic converter heat shield. It's that rattly metal noise. But I've checked every heat shield, used a rubber mallet on every converter to check for chunks in a converter, and even pulled off the exh manifold heat shields.

The noise is not there at very high throttle positions, but is there at lighter throttle, during acceleration. The noise goes away every time the trans shifts (presumably because the load of the motor is reduced as torque management pulls timing during the shifts). The noise cannot be pinpointed, and I'm very experienced with working on cars. After 2 years of trying to figure this out, and listening to it carefully all the time, I've come to the conclusion its possibly coming out of the tranny or converter. Does this symptom match anything you've experienced on Explorers?

It's a somewhat common Explorer problem, that I do know. And Ive heard the timing chains (4.6 2v) can make that noise if the chain eats thru the nylon in the guide. Problem what that good theory is no aluminum specs in the oil, and hasn't gotten worse in 30k. I'm really thinking it could be converter/trans noise, but have never heard such a noise out of a functioning tranny. Any thoughts?

 

[BrooklynBay]

Your post was moved into its own thread with a new title in the stock 2002-2005 section. Does the noise change with temperature?

 

[irocdupi]

Could be youre torque convertor. Mine sometimes make the noise when the truck is first started and im driving. Once the transmission heats up it quiets down to the point where I cant hear it.

 

[Pontisteve]

I'm thinking it might be in the trans or converter, but I've never heard a noise like that from a tranny. Sounds like rocks in the catalytic converter, but it's not. Or like a very loose cat heat shield. Or maybe even like a timing chain noise, but that doesn't seem to be it either.

Cracked flywheel? converter? Anybody with an explorer ever have noises like this? It only happens at part throttle acceleration. WOT throttle it goes away, or at least i can't hear it over the motor. When the converter locks up, it goes away. While the truck is shifting, and torque management is pulling timing during the shift, it goes away.

 

[irocdupi]

Its the infamous torque converter rattle. Exactly what your describing. When the converter locks the rattle goes away. Its your torque converter

 

[Pontisteve]

Infamous eh? I take it this is a very common problem? Whats the fix, a new converter? Does it cause any damage, get to the point where it fails? What can I expect out of it?