Got a whining noise coming from under my car which start from when you set off and doesnt stop at speed. I've removed the prop and it's not as loud but is still there. Does this should like the common transfer box problem. I've got a blanking plate to remove the pinion see if it might be that. Anyone else any thoughs on this. Thanks
Yes, it could be. If you take the pinion out, it leaves quite a big hole. You might be able to poke something in and see if there's play in the shaft with the crownwheel on it. The bearing that fails first in most IRDs is the big taper roller bearing closest to the crownwheel.
Nodge68
Well-Known Member
As GG said. Make sure you remove the IRD filler plug before draining the oil, although it is possible to get an mount of oil in through the rear of the casing, once the rear output pinion is removed.
Nodge68
Well-Known Member
75w90 fully synthetic. Although if the oil that comes out it full of particulate matter (metal flecks), the you'll need to change it a few times, which means a semi-synthetic oil can be used for short time spans.
GrumpyGel
Well-Known Member
Even in a IRD in good condition there can be/will be a build up of metallic sludge on the drain plug - its a case of how much and what the oil looks like.
I say this not to be-little the previous post in any way because its pretty obvious there stuff on there that shouldn't be! But just not to condemn an IRD just because there's a bit of sludge on the drain bolt.
I say this not to be-little the previous post in any way because its pretty obvious there stuff on there that shouldn't be! But just not to condemn an IRD just because there's a bit of sludge on the drain bolt.
OK, understood, but what I should have also said, is that the photos above were taken after the oil had been in for only 2000 miles! I changed the IRD oil when I first got it (as it had never been done!) and it came out with similar amounts of metal in it, but blacker. I then ran it for 2000 miles and dropped the oil, and the above was the result. Sure, I can accept that a bit of sludge on the magnetic plug might be a reasonable expectation - (or else, why put a magnetic plug in there!) but if the plug has "caught" as much as it can hold and the oil is STILL full of particles, I guess that's a sure indicator of a problem?
Here's the failed bearing when I got it out. There was visible play in the crownwheel when I dismantled it. Probably a couple of mm at the rim of the crownwheel.
GrumpyGel
Well-Known Member
I was reading an article on how bearings fail. It said they basically overheat and deteriorate. You can see in those pics how that may have happened with chunks having been stripped from them. They haven't just 'worn down' or else presumably they would be all shiny.
Nodge68
Well-Known Member
What's on the drain plug has some use as an indicator of condition. However the mag-plug is there to remove ferrous material left over from manufacturing and "break in" period. As you say, the condition of the oil is far more telling as to the condition of the bearings.
jamesmartin
Well-Known Member
the bearing wears over time till hard facing is worn through the softer center does then pit,the increased friction creates heat and burns oil into the surface
Yeah, it's not something I know much about. I had a feeling that the rollers and races were only surface-hardened, so as they wear, they look pretty shiny and normal, but as soon as the hard layer is worn through, they start to break up like mine did. It's a bit of a "chicken-and-egg" situation, I think. As the bearings wear and the meshing teeth go out of alignment, there's a bit more friction between the teeth as they rub over each other, which generates a bit more heat. I don't know if it's that which "cooks" the oil, or whether the oil starts to lose its lubricating properties, so there's more heat anyway? (Or a bit of both)? I'm assuming the darker colour of the oil, is down to degradation by running excessively hot? The first oil had been in there (as far as I know!) for 150,000 miles. I could forgive it for being black and not very good at lubricating! The second oil (in the photos) had only been in for 2000 miles, but was also pretty black - although I don't know if that was overheating or just picking up blackness from the dregs of the previous oil?
They look like extreme examples of the first couple of photos in this article:
https://www.timken.com/wp-content/uploads/2017/08/MDV2-Tapered-Roller-Bearing-Damage.pdf
Ah, you beat me to it!
More stuff here, but really talking about grease-lubricated bearings rather than oil.
https://www.timken.com/pdf/5892_Bearing Damage Analysis Brochure.pdf
Still, everything seems to suggest that mine failed by contaminated lubricant with metal particles in it that were higher than the lubricant film thickness?
https://www.timken.com/pdf/5892_Bearing Damage Analysis Brochure.pdf
Still, everything seems to suggest that mine failed by contaminated lubricant with metal particles in it that were higher than the lubricant film thickness?
And this one seems to suggest simply "old age"?
https://www.schaeffler.com/remoteme...ownloads_24/barden_bearing_failures_us_en.pdf
https://www.schaeffler.com/remoteme...ownloads_24/barden_bearing_failures_us_en.pdf
jamesmartin
Well-Known Member
the bearing race in your pic looks like failure from wear not contamination, its shiny and dosent have the speckled effect from debris pressed into the surface
Nodge68
Well-Known Member
Bearings are case hardened and polish ground to the exact surface dimensions needed for the application. There are two main bearing failure modes. The first is simply due to wear over time. This wear is normally due to microscopic particles in the oil, wearing the hardened surface off.
The second type of failure is due to overload. In overload situations, the case hardening can literally peel off softer base metal, due the the constant high pressure on the bearing surface. This high pressure will de-laminate the case hardening off the base material. This is the most common failure mode for the IRD bearings.
The second type of failure is due to overload. In overload situations, the case hardening can literally peel off softer base metal, due the the constant high pressure on the bearing surface. This high pressure will de-laminate the case hardening off the base material. This is the most common failure mode for the IRD bearings.
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