Grayish rear diff fluid - Toyota 4Runner Forum

amir_gh · 11-18-2020, 09:50 AM

Hello,

I replaced my rear diff fluid on my 2016 limited with 48k miles . Mine took about 3 quarts. Oil condition was absolutely terrible. It was grayish color. Never seen that before. Does that grayish color mean anything?

Thanks

bak3rme · 11-18-2020, 10:34 AM

sounds like maybe some water got into the diff thru the breather? Either that or you are cooking fluid. are u running 6s down the 1/4?

amir_gh · 11-18-2020, 10:38 AM

Quote:

Originally Posted by bak3rme

sounds like maybe some water got into the diff thru the breather? Either that or you are cooking fluid. are u running 6s down the 1/4?

Got my truck used. Everything is stock. No modifications. Previews owner never replaced it

bak3rme · 11-18-2020, 10:42 AM

I'd say get underneath and look on top of the diff for the diff breather. is there fluid coming out from that area? My guess is that maybe water somehow went through there and mixed with diff fluid. Interested to hear what others have to say about this.

5thToy · 11-18-2020, 10:43 AM

Sounds like water contamination. It wouldn't necessarily have to come in through the breather. If the rear was hot and took a trip through a nice cold stream, water can be pulled in by vacuum through the rear axle. This is why people install elevated rear breathers that stay open to atmosphere.

sawman1 · 11-18-2020, 11:19 AM

Almost guaranteed water intrusion. As noted above, check the breather for possible intrusion. If all appears OK, I would run it for a bit and service it again to be sure the fluid looks OK, or at minimum pull a sample to inspect. 20+ years in the business so I am going off some experience when I type this. Best to you.

amir_gh · 11-18-2020, 11:29 AM

Quote:

Originally Posted by sawman1

Almost guaranteed water intrusion. As noted above, check the breather for possible intrusion. If all appears OK, I would run it for a bit and service it again to be sure the fluid looks OK, or at minimum pull a sample to inspect. 20+ years in the business so I am going off some experience when I type this. Best to you.

Thanks. I will keep eye on it.

amir_gh · 11-18-2020, 11:40 AM

Quote:

Originally Posted by bak3rme

I'd say get underneath and look on top of the diff for the diff breather. is there fluid coming out from that area? My guess is that maybe water somehow went through there and mixed with diff fluid. Interested to hear what others have to say about this.

Any suggestions for Diff breather kit? Can I do this myself?

Thanks

Captsolo · 11-18-2020, 11:53 AM

Quote:

Originally Posted by amir_gh

Hello,

I replaced my rear diff fluid on my 2016 limited with 48k miles . Mine took about 3 quarts. Oil condition was absolutely terrible. It was grayish color. Never seen that before. Does that grayish color mean anything?

Thanks

I did mine after ten years. Color was pitch black. Gray might indicate some moisture, might not mean anything.

Check it in three years again.

Twilghtzone · 11-18-2020, 12:14 PM

Hmm... Truck might have been in a flood ? I'd check the other differential, trans, and transfer case.

pDubs · 11-18-2020, 12:29 PM

Greyish diff fluid in a 4runner is hardly enough evidence to say it may be a flood vehicle.

As other mentioned, if you went through a water crossing or even big enough puddle on road water could have gotten in. I would change again in like 10k miles and check since it's easy enough to do.

I did the ARB diff breather kit just because it was already all pieced together but there's a few cheaper ways to get the breather and bung from Toyota and use fuel line to run up to engine bay or near gas filler.

Amazon.com: ARB Differential Breather Kit (170112): Automotive

LandCruiser · 11-18-2020, 12:31 PM

Water intrusion during some type of water crossing IS the most likely culprit, doesn't have to be off road.

If there's water in one diff, as others said I'd check everything else, too.

PO wasn't from Houston, was he?

delloro · 11-18-2020, 12:54 PM

Quote:

Originally Posted by amir_gh

Hello,

I replaced my rear diff fluid on my 2016 limited with 48k miles . Mine took about 3 quarts. Oil condition was absolutely terrible. It was grayish color. Never seen that before. Does that grayish color mean anything?

Thanks

Was it more like graphite, or milky?

Graphite color is OK. Milky means water.

kenwilliams0803 · 11-18-2020, 12:57 PM

Quote:

Originally Posted by delloro

Was it more like graphite, or milky?

Graphite color is OK. Milky means water.

Yeah, after almost 90k on factory fluid I'd suspect a little bit of metal flakes in there, almost like the color of never seize. I wouldn't rule out water intrusion though either and I'd bet you're good for a while now that it's all cleaned up and fresh.

amir_gh · 11-18-2020, 01:14 PM

Quote:

Originally Posted by delloro

Was it more like graphite, or milky?

Graphite color is OK. Milky means water.

defiantly graphite

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