08, 4.0 4x4: Very faint "rattle" goes away when i push in clutch

[cmattina]

So, the truck is relatively new to me, the newest truck i've ever owned. It only has 70 000km on it... so about 40 000 miles.

I changed the tranny fluid when i bought it (this summer), and all the other fluid looks fine.

Either way, whether i am at idle or driving, i hear a very faint rattle, i actually thought it was probably just a little valve noise, until i realised it goes away when i push the clutch in. This is when i am in neutral at idle, or shifting from any gear while driving. I should emphasise that it is very faint. Most people wouldn't hear it, but i'm a little anal about these things - like compared to what i've seen in youtube videos which sound like marbles in can, this is not that.

I've done a bit of research, and found a couple different answers.

Any opinions? I figure i am in for a clutch job down the road, but curious how long i got and why? Could it be fluid related? The dealer sold me MERC V and that's what I used, seemed to take slightly less than I expected, but less than a liter's difference (it still drips out slightly when i take out the fill plug)

 

[adsm08]

I doubt it is fluid related. Merc V is the right stuff for that trans.

It could be a throw out or pilot bearing, and I know this sounds screwy, but there was a TSB on the cats around that year, the one on the driver's side would collapse and usually the only symptoms were a check engine light, and/or a rattle noise.

I only bring that one up because the very first one of those I ever saw the guy said the noise changed when he put the clutch down. I did the TSB because he had the cat code stored in memory, and when I turned it over a pile of sand showed up on my floor.

 

[cmattina]

I doubt it is fluid related. Merc V is the right stuff for that trans.

It could be a throw out or pilot bearing, and I know this sounds screwy, but there was a TSB on the cats around that year, the one on the driver's side would collapse and usually the only symptoms were a check engine light, and/or a rattle noise.

I only bring that one up because the very first one of those I ever saw the guy said the noise changed when he put the clutch down. I did the TSB because he had the cat code stored in memory, and when I turned it over a pile of sand showed up on my floor.

Thanks (as usual).

I have a cheapo OBDII scanner and have no codes showing up when i use it, would a better scanner show more codes (stored?).


I guess there is no other way to check the cat? Maybe i'll get out the stethoscope?

 

[adsm08]

Thanks (as usual).

I have a cheapo OBDII scanner and have no codes showing up when i use it, would a better scanner show more codes (stored?).


I guess there is no other way to check the cat? Maybe i'll get out the stethoscope?

No, a better scanner won't show more codes. That is 10000% not how that works.

The only way to check a cat with a scan tool is to watch the upstream and downstream O2 sensor signals and compare them. If you know what you are looking for/at you can detect a weak cat before the monitor sets a code.

 

[cmattina]

No, a better scanner won't show more codes. That is 10000% not how that works.

The only way to check a cat with a scan tool is to watch the upstream and downstream O2 sensor signals and compare them. If you know what you are looking for/at you can detect a weak cat before the monitor sets a code.

Yeah, i am familiar with checking the figures within the program (not VERY familiar, but have seen it done by someone more skilled than I). My scanner doesn't show it, but i think i can DL the program to do it, though i'm missing the interface tool. If it is a rattle i am hearing i assume i can narrow it down between the clutch area and cat with a stethoschope.

 

[RonD]

If rattle goes away when you push in the clutch pedal then it is throw out bearing and it could run years before it is a problem.
Maybe Pilot bearing but doesn't matter really since you would replace both if you pulled transmission off.

With engine off, tap on mufflers and Cats with rubber mallet or 2x4(piece of wood), listen for rattles.
Do it with cold exhaust system, then do it again when it is hot

 

[cmattina]

So,

My coworker has an '01 with 100 000km (65 000 miles ish), with the 3.0.

I just went and listened to it on coffee break. His makes the EXACT same noise and it goes away when pushing the pedal in.

It was amazing how the noise was to a T, the same.

Oddly, maybe just a coincidence. My co worker has a habit of always starting from a stop sign in 2nd gear. When i bought my truck i went for a test drive with the guy who sold it to me and he did the same thing (and was the original owner)... i wonder if that has anything to do with it. My co worker has owned his for 5 years-ish,

 

[cmattina]

If rattle goes away when you push in the clutch pedal then it is throw out bearing and it could run years before it is a problem.
Maybe Pilot bearing but doesn't matter really since you would replace both if you pulled transmission off.

With engine off, tap on mufflers and Cats with rubber mallet or 2x4(piece of wood), listen for rattles.
Do it with cold exhaust system, then do it again when it is hot

I am thinking the same thing... I am trying to determine if there would be damage if i didn't fix it?

 

[RonD]

No, no damage.
Would just get louder until you got sick of the noise or wanted to change the clutch because of miles/age