I have a 97 F150 4x4 with 83000 miles on it and just changed the front diff oil for the first time. It was a light gray in color, does this mean anything? I put in Castrol 75w90, GL5. This is a nice amber color. Any thoughts? TIA.
Front Diff oil gray when changed.
- Thread starter SigShooter
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If you kept some try putting some in a glass jar and let it sit for about 3 weeks. You will see that, unlike motor oil, the grey settles out to the bottom as a paint-like sludge and the oil returns to a yellowish state. Of course, I would not re-use the oil anyway. This is also why checking your front diff when it has been parked a while or has not been put in 4by in months is not a good indication of the state of the oil.
If there is a big worry about a problem with the component send the the oil to an oil analysis company if you have it. Then share the results with us. Now I will get on my soap box and preach . Changing all the fluids in your vehicles on a regular schedule ,See the factory manual, will be one of the best things that can be done to get the longest life out of your vehicle. The oil is old and there is condensation and front differentials in 4 by 4's have lots of thrust bering loads on them when steering.
Axles are always neglected...bulletin out now at the big three if you don't do regular diff drain and fills NO warranty work will be covered
I doubt that the grey color comes from normal wear. I think it is an additive.
When the ring and pinion break-in and establish their contact pattern the metal that was removed from them goes somewhere...changing the fluid with-in the first few thousand miles makes a big difference down the road in axle life...I've changed some pretty nasty looking gear oil in my 30 or so years doing it
I changed the rear fluid on a 12 bolt chevy ss camaro that had gone 10 years and 180k miles and it came out about the same as the black tar that is used to patch the roads with. Actually came out like cold tar.quote:
Originally posted by Greaser:
When the ring and pinion break-in and establish their contact pattern the metal that was removed from them goes somewhere...changing the fluid with-in the first few thousand miles makes a big difference down the road in axle life...I've changed some pretty nasty looking gear oil in my 30 or so years doing it
Having never seen the oil which goes in at the factory to compare with the oil that comes out with the first oil change I can't say for sure.
i'll have to agree. i've probably changed 100 gear sets, 90% of them in fords. the earlier ones had clear gear lube, even with 100k miles. around '96, they started getting a thick, charcoal, murky looking lube.
i've had rearends open within a few thousand miles of new gearsets, there's no evidence of any wear or metal. i'm sure it's there, we just can't see it. less than the mettalic flakes you can see with a flashlight in used engine oil, anyhow.
I changed the rear axle on my T-bird after 15 years of not changing it.
The fluid came out grey, with BLACK tar on the bottom. Turns out the black "tar" was metal particles that just sat down into the bottom of the carrier (no magnetic fill plug).
If you look at the Ford 8.8" rear ends, with the magnetic fill plug - the fill plugs are almost always covered in some gray paste. That paste is metal.
The fluid came out grey, with BLACK tar on the bottom. Turns out the black "tar" was metal particles that just sat down into the bottom of the carrier (no magnetic fill plug).
If you look at the Ford 8.8" rear ends, with the magnetic fill plug - the fill plugs are almost always covered in some gray paste. That paste is metal.
It still amazes me how the axles don't cough their guts sooner the way people abuse them.Had a guy come in with his pants in a bunch saying "my axle runs so hot I can hardly put my hand on it".It's normal I told him.On a hot day with highway miles behind it EVERYTHING runs hot.I changed my lube the first 1000 miles,again at 5000,then again at 10,000.After that every two years or 30,000 miles..all synthetic...both axles front and rear and don't have a peep coming out of them.One guy was pulling a boat for two years with a Dana 35.When I took of the cover a thick,silver liquid came out...side gears were toast...1500 bux later he's changing his axle lube regular now
"Randy's Ring&Pinion" shop has a great website print-out for break-in procedure.
please see my post. What kind of additive would settle to the bottom and need churning to keep it in suspension? In my case, if it was an additive it is a sorry one and not listed in the manual. BTW mine is a 93 ford xpl, I do not know what the new pumpkin fills look like but mine was certainly grey at 70k. I put Mobil 1 in and now have 180k.
MolaKule
Staff member
The gray stuff you see is metal paste, wear metals coming from the bearings and teeth. At least the fluid kept those in suspension for you.
If you had had a magnet on the cover or a magnetic drainplug, you would have seen a thicker paste around the maggies.
The black stuff is hydrocarbon breakdown due to oxidation and acids.
I don't let diffy fluid go more than 30,000 miles before I change it, due to analysis of many different fluids in the past.
And if you're towing, 15,000 miles should be max. I work with a local diffy shop who repairs differentials of all types and also builds racing differentials. The highest repair diffys are Chevy 10 bolt units on light trucks.
If you had had a magnet on the cover or a magnetic drainplug, you would have seen a thicker paste around the maggies.
The black stuff is hydrocarbon breakdown due to oxidation and acids.
I don't let diffy fluid go more than 30,000 miles before I change it, due to analysis of many different fluids in the past.
And if you're towing, 15,000 miles should be max. I work with a local diffy shop who repairs differentials of all types and also builds racing differentials. The highest repair diffys are Chevy 10 bolt units on light trucks.
I just changed the diff factory fill on my 99 E-150 at 25K with no towing/abuse. Put in Sta-Lube Syn-Go 75w-140 plus Trans-X FM. The soup I pumped out was metalic charcoal grey, and a sludge was on the magnet fill plug.The odd thing was the odor of the Sta-Lube oil made my wife sick to her stomach!I had to air seal the rest in another container! She was not happy and thought the stuff would smell up the van!The stuff does sorta stink.Beware guys, the wife may take offense.
Ron
Ron
Doesn't your wife like the smell of sulfer?Boy she wouldn't like the aroma of our moose campquote:
Originally posted by Ron:
I just changed the diff factory fill on my 99 E-150 at 25K with no towing/abuse. Put in Sta-Lube Syn-Go 75w-140 plus Trans-X FM. The soup I pumped out was metalic charcoal grey, and a sludge was on the magnet fill plug.The odd thing was the odor of the Sta-Lube oil made my wife sick to her stomach!I had to air seal the rest in another container! She was not happy and thought the stuff would smell up the van!The stuff does sorta stink.Beware guys, the wife may take offense.
Ron
Actually, she got her chemical hyper-sensitivity to various odors from prolonged exposure to working with polyester resin.No, she did not make surf-boards. But, it's kinda good, cause now if the radiator leaks, fuel, whatever, she can sniff it out like a hound! It does also force me to keep up on my own BO, not to mention BS.
Ron
Ron
And people here crackup when I tell 'em I buy Redline gear oil at A$30+ per quart for my diff/gbox. I still believe it's THE best money I've spent when you think how long it will be in there and what it has to cope with!
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