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Discussion Starter · #1 · (Edited)
Hey, just wanted to see if anyone knows what this grey dust inside the bellhousing is? Heavy off-roader in the desert and been having a CPS sensor issue so i removed the gearbox and noticed a lot of sand mixed with grey dust inside the bellhousing. Car is automatic transmission, 4.8VTC, 2017
Anyone have any idea? Is this normal?
 

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1988 Maverick TD42,
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Collect a good amount of it, form it into a pile on a peice of paper, see if it conducts electricity. If it does, see of it is magnetic. That should get you pretty close two a few key material groups.

I have no idea about the main question however....
 

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'14 Y61 ZD30 CRD M/T ST
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Is the dust dry or is it lumpy? Does it look like it’s mixed with oil? Is there any sign of oil leaking from either the engine, torque converter or gearbox?
Have you removed the flex plate. What does the crank seal look like?
What does it look like behind the torque converter? Are the gearbox seals OK?

I presume the “dowel like” thing protruding into the bell housing is the infamous crank angle sensor that keeps getting damaged…? Does that get it’s signal from the flex plate? Is there any damage on the flex plate? Is there any signs of it impacting the sensor? Have you checked the flex plate for run-out?

If there was any radial play in the crank and/or transmission input shaft that would cause the flex plate to move radially at all, you’d have much bigger problems than just the crank angle sensor being knocked. If it is indeed caused by interference between the flex plate and sensor, the only explanation I could fathom, is that there is some sort of harmonic imbalance that causes the flex plate to distort and become “oval” at a certain rpm/load. Maybe you need a stiffer aftermarket flex plate or something… :unsure:

I’m clutching at straws here… I really have no idea how that sensor is getting damaged, but I’m not convinced the dust and sensor issues are necessarily related.
 

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Discussion Starter · #6 ·
1. Dust is extremely dry and not lumpy at all. The second you touch it, it feels super soft, almost feather like.
2. No Leaks from any side of the transmission or torque converter. It does seem like the torque converter has been very polished up through a bunch of sand being inside the bellhousing from off-roading. The converter is absolutely spotless.
3. Yes, the flexplate was removed and the crank seal seems to also have a bunch of this grey dust around it but it was much more dense and compact. Checked for leaks all around and it doesn't seem to have any whatsoever. Oil level in the engine is good and no visible leaks anywhere around either.
4. Yes, that is the CPS sensor coming out the top of the bellhousing. Its signal reading is from the flexplate. No reluctor ring on it behind either. (Some other cars, y62 do have that. Flexplate run out has been checked by the dealership and they mentioned everything is fine too. This is also a brand new genuine flexplate which was purchased and installed on Sept 1st.

I was told by a friend that the starter motor run with a carbon brush system or something a long those lines which is why there is grey dust. Mentioned that the qty of it is so much as sand is getting into the bellhousing through off-roading.
Nissan found a small hole near the starter motor mount which should be sealed however wasn't. Not sure about why but couldve been when they replaced my engine a year and a half ago.

Should be picking up the car this evening from the dealership and will go for a test in the desert this saturday morning...Lets see what comes off it.

Will keep you posted
 

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I'm wondering if the grey dust is sandblasting dross from the paint off the torque converter and aluminium oxide from the inside of the bellhousing. I know that sand always gets in everywhere (like red dust) but I'm a bit curious how so much got inside the bellhousing of an auto.
 

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Y2KGUII ZD Wgn
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I'm wondering if the grey dust is sandblasting dross from the paint off the torque converter and aluminium oxide from the inside of the bellhousing. I know that sand always gets in everywhere (like red dust) but I'm a bit curious how so much got inside the bellhousing of an auto.
Me three, been following this and something strange is going on, not seen something that bulky before.
 

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Discussion Starter · #9 ·
Yeah, its a very weird issue to be honest and i usually drive with several y61s offroad in the desert. All of us drive pretty hard and no one else seems to have this issue...Also had this car for 2 years and was off-roading a lot more before so not sure why this issue did arise previously. Seems to be only after my engine replacement. They did say they also think the sand entry in the bellhousing is basically sand-blasting the sensor and the rest which is causing this issue but I'm still not fully convinced. Once the car is back together, and i go for a test this coming weekend, will keep you posted.
Ill try to get the picture and video of the amount of sand that came out when they opened the bellhousing this time, it was a fair bit of sand.
 

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Discussion Starter · #10 ·
So i think it may have been sand mixed with the carbon emitted from the starter motor carbon brushed, combined with bascially sand blasting the bell housing and the torque converter.... Below is the pics and videos of my transfer case....
 

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Hi Team,
also been following this saga.
I assume the grey is due to sand blasted aluminium from the alloy housing along with some grey when the sand gets finely ground to a white/grey powder by the starter gearing meshing and crushing said sand--the starter is a sealed unit and black carbon brush material is contained within the starter itself.
The sensor failures would have been due to it being sand blasted by the sand when it is whirled around in the housing by windage caused from the rotating flex plate, ring gear and T/Converter--basically anytime the engine is running the sand is being whirled around in the housings like a dust storm--some one suggested this earlier if I recall.

Believe it or not, early Caterpillar No12 Motor Grader oil clutch cooling/lubricating oil return system used the flywheel windage to return engine oil pumped into the main clutch for cooling and longevity to throw said oil into a catch tray cast on the inside of the clutch housing and then return the oil by a gravity return pipe to the engine sump.

My two bobs worth anyway.
Regards,
Eddie B.
 
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