I've developed a whine in a just 10 miles of driving

[mibars]

Hi,
Recently on my 16 km/10 mile commute back home Burb has developed a pronounced whine under acceleration. I just power washed it throughout, focusing on undercarriage to get rid of a road salt after winter, so I suspected that I managed to somehow introduce water into the axle via the vent above the gas tank.

I found no water in the oil, level was exactly as it should be, however it was dark and glittery and I found no magnet inside the housing. No chunks, but there was a layer of sludge. There was no play between ring and pinion, although there is some play in the satellites that translates to the slop between driveshaft and wheels. (video below). That's the 1st diff I ever open, but compared to what I found online the ring and pinion seem okay.

Oil changed, new magnet RTVed to the case, but the whine remained. I've just travelled 16 km to work on fresh clean oil and the whine got even louder, I start to hear it on a deceleration too.

Am I looking in a wrong place? Transfer case or gearbox issue? Could a diff go from OK to loud in 10 mines?

Any guesses welcome.

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[ali_c20]

That's a lot of play in the spider gears. I would replace them.
Get a kit with washers and gears from a reputable company.
My 0.02$

https://www.youtube.com/shorts/uBDbxEZFRMM

 

[ChuckN]

That does seem to be a rather quick transition. I’ve had GM rear gears howl but it was a very slow wear transition.

With the play in the spider gears, is anything more pronounced during turning than going in a straight line? As I understand it, that’s when the spider gears come into play.

I’d probably check all the fluids, but that’s how I roll. Someone with more acute knowledge will likely chime in.

 

[74Blaze]

I've developed a whine in a just 10 miles of driving​

Man-up. Nobody likes a whiney square-body owner.

 

[mibars]

I’ve had GM rear gears howl but it was a very slow wear transition.

That's my biggest worry: Why so fast? I'm no stranger to drivelines making funny noises, my previous daily driver has developed a whine over much longer period of time, amplified by an accidental clutch drop at one time. I also had Hondas with noisy diff and transaxle and they just kept going that way until I get fed up with the sound. Here: Nothing like this. From no noise to sounding like an old bus in just couple of miles and seems progressing too quickly.

The spider gears are stationary in a straight line driving and I don't see anything change in turns. That play actually made me less worried as I was afraid that the play may be between ring and pinion or on an axle shaft. Maybe the diff had too many one wheel peels in past, who knows, it's an auction vehicle from Washington

 

[ChuckN]

That's my biggest worry: Why so fast? I'm no stranger to drivelines making funny noises, my previous daily driver has developed a whine over much longer period of time, amplified by an accidental clutch drop at one time. I also had Hondas with noisy diff and transaxle and they just kept going that way until I get fed up with the sound. Here: Nothing like this. From no noise to sounding like an old bus in just couple of miles and seems progressing too quickly.

The spider gears are stationary in a straight line driving and I don't see anything change in turns. That play actually made me less worried as I was afraid that the play may be between ring and pinion or on an axle shaft. Maybe the diff had too many one wheel peels in past, who knows, it's an auction vehicle from Washington

Yep! I’m not familiar with your truck but you mentioned a transfer case- did you check that fluid? I’d just go through everything.

I’d say that, if you’re comfortable with it, getting it off the ground and putting it in gear (letting the driveline spin) and putting a long screwdriver to the the ear might help you isolate it- but if it’s not under a load, that might not be helpful.

 

[mibars]

On a way home I've recorded couple of audio samples. Kinda sounds different on my phone than on Youtube, but lets say close enough.
Some additional noise has appeared, I'd say metallic? This makes me wonder if it's a bearing somewhere dying or what.

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Transfer case: I'll definitely check it as I have a very slow leak, like a drop or two a day. I do check it every now and then, but maybe?

 

[DoubleDingo]

I am not hearing any whine. Sounds like aggressive tires and exhaust. If you have a gopro and a way to clamp it or mount it underneath, do that so it will be closer to the sound.

 

[mibars]

I have relatively quiet A/T tires and at that point the exhaust bypass was fully closed, you can barely hear the engine.
This whine sounds much lower than a whine I've developed in WRX, or inherited in a short ratio diff of my S2000. Adding that odd metallic sound that has appeared it makes me think that maybe a bearing somewhere has decided to stop doing it's job.

 

[DoubleDingo]

The way you've described it, yeah, sounds like it could be a bearing

 

[Sad Sack]

A whine after 10 miles of driving? Sounds familiar, I had that problem before as well then we divorced… no more whine.

 

[Turbo4whl]

Maybe the diff had too many one wheel peels in past, who knows

When one wheel is spinning, the differential side gears and pinion gears are spinning at twice the speed. As stated by @ali_c20 and @ChuckN the spider gear bushings /bearings seems worn. Something else, those gears look like they a starting to have cavitation.

You have heard of hyd pump cavitation, this happens when the pump runs out of oil. Well this can happen to the diff side and spiders gears too. They are in oil, then out of oil, like a pump running out of oil. The metal removed each time is small, but can build to a muck in the rear.

The ring gear is throwing oil to lube the pinion bearings. If there is enough build up of muck, the ring gear throws that at the pinion too. Now those bearings are wearing too.

I have relatively quiet A/T tires

Tires get louder fast if one tire is low on air.

 

[mibars]

Could having too much ATF in a transfer case screw something up? I've drained like a quart from a fill plug (2nd time this happens, last time I've had to add like an ounce, so it's random) and since the ATF came out dark I've changed it. I suspect the darkness comes from the clutch material from the gearbox leaking into transfer case.

 

[DoubleDingo]

If it's dark, may be time to drain and fill to get fresh in there

 

[mibars]

I did change it once I've seen the color.
Anyway I think it's beyond my diagnostic capabilities. I'll take it to the shop to see what's going on.