How much glitter in rear diff fluid is normal?

I’ve got a 2004 Tacoma with 264k miles on it, just change the rear diff fluid and it had quite a bit of glitter in it. I tried to post some pictures but they weren’t loading so I’ll try to figure it out, in the meantime how much glitter would everyone consider normal in a diff? Thanks in advance.

 

Shouldn't be very much at your mileage, especially if the diff oil has been changed on schedule throughout the life of the truck. Also, by glitter, I'm wondering if you mean sparkly flecks of metal, versus gray sludge that sticks to the magnetic drain plug. A little gray sludge is normal, but "quite a bit of glitter" sounds alarming.

 

Some silver sludge on the drain plug but mostly just a lot of silver glitter in the fluid itself. No metal chunks or anything like that though. I don’t know, with the mileage I have it’s probably time for a new diff

 

Meh


If you didn't see any SOLID chunks (and I mean something you could physically pick up out of the oil by itself) you don't really need a new diff yet. There's a good chance the previous owner didn't change the fluid at regular intervals and it's just the total amount of debris that'll happen.

Take this with a grain of salt cause it's about a Ford 9" rear but, I can tell you from personal experience, I changed the diff fluid at 212k and I don't think it EVER got changed ... Black as sin and stunk to high hell. Not my picture but the oil looked slightly worse than this

I was for sure the gears were gunna take a shit on me but I drove it for 60k before selling it without any issue and no "howling" noise developed. IMHO Toyota build axles better than Ford so you should be fine so long as no SOLID pieces were present

 

Can't say I've ever noticed glitter in mine, aside from the sludge that sticks to the magnet. Glitter is better than big shavings or chunks though. I would put fresh oil in it and check it again in maybe 15 - 20k miles and see what it looks like. Might just be that it's been many years/miles since it's last change and it looks worse than it is

 

Interesting. I drained it into a caddy so I didn’t get to see the full amount of fluid, but I ran my finger through the fluid and it looked pretty silver. I’ll probably drain it again in a week or 2 and see how it looks.

 

I had a shop change it 5k miles ago. So either I got ripped off and they didn’t change it or that diff is really in bad shape, but I feel like if that was the case it would’ve blown up already. Only reason I was changing it is because I went through a deep water crossing on the trail and wanted to make sure I didn’t have any water in there (there was none).

 

IMO going a couple more weeks and draining again is more work for nothing. If it took 264k to develop that much a few weeks (another 1k max?) won't produce meaningful data. The magnet will hold all the steel and iron swarf, the non-ferrous stuff will stay in suspension and won't cause much additional wear. The rear end will start howling pretty good coasting and on decel if it gets to the point you need to address it.

Edit - just saw the shop might have changed it 5k ago - seems suspect. How hard have you been driving it?

 

I would look into relocating your rear diff breather if you do water crossings on occasion. The stock breather is right on top of the axle and it doesn't do you any good when it gets submerged. And if it gets plugged up with dirt/debris the diff can't vent air and you'll blow your axle seals

 

Im a tech (entry level) at a Toyota dealer so it’s not a huge amount of work to change it, but I agree it probably wouldn’t produce any results. Would it make noise only on decel or throttle too? I don’t drive the truck hard at all. I take very good care of it.

 

I usually try to stay away from water crossings unless I have to. In this case I had to cross it as I had no way out the way I came, but I agree with you I’ve been wanting to do that mod just keep forgetting to.

 

@Indyteecee based on all your other comments it sounds to me as if your being overly cautious... which when you're new (you stated being an entry level tech) is a good thing. You just haven't had a broad range of repeatable experiences yet to fall back on, stick with it and you'll get there.

When you changed your fluid after the water crossing how black was the fluid?

did it smell god awful... something worse than it is outta the bottle?

Was it a hole in the wall kinda shop?





Depending on your answers to the above inquiries, my gut says they took you for a ride and did not change the fluid.


I rebuilt my entire drivetrain about 10k miles ago (transmission, transfer case, and front and back drivelines) , but due to money constraints could only change diff fluid front and back instead of rebuilding em like I want to.

I Just changed my engine oil and I noticed an axle seal is leaking... when I ran my finger across the leak on the axle tube, the diff oil was still very see through. And that's after almost 10k miles. If your fluid was dark and extra stinky, imma say your fine.





Years ago I had a 93 GMC Sonoma that had bad rear gears, sucker HOWLED! Accel, Decel, real quietly on coast.. didn't matter, it made some kinda noise. Again not my pic but my gears were worse than this but not that much worse



Understand that once you cook the heat treatment off those bevel gears they go downhill FAST.. but, in my experience, if it's not making noise... it's not dying yet

 

I just swapped the diffs in my 89 Supra, and the original with 239k would be reasonably quiet on accel but any time I was just cruising it would get a little noisy. On decel however, it sounded like a wookie under the seats. Swapped to a different one and couldn't believe the car was so much quieter all the time.

When I drained the fluid in the old one, it's magnetic plug had grown to twice the magnet thickness with all the metal dust it was collecting.Fluids changed for sure between 160-170k and smelled absolutely awful. All those good friction modifiers.