How does a front diff make fluid?

[TravisHTX]

Got a mystery for yall, maybe you guys have seen this before. I took my 19' in for a state inspection to a local shop, and had them just check the front and rear diff fluid while it was there. Apparently when the tech pulled the fill plug on the front diff, fluid started coming out of the fill port!

The reason I had them check the diffs was because I had been through some high water, and just wanted to see if there was any indication of water in the diffs. Also, a while back, I had to replace a front axle assembly (long story), and when I pulled the original out, I lost some fluid, maybe 8 oz or so, so I was thinking the front diff was going to be low.

So how can a front diff make fluid? About the only thing I can think of is that it was overfilled from the factory. The tech said there was no indication of water in the fluid.

Couple additional questions for you guys on the subject of the front diff. If the front of the truck is level, and you pull one of the axle assemblies out, I was under the assumption that it should be full enough that fluid gets to the seals, so losing some fluid may be normal? Also, is the front diff cover put on with a paper gasket or a liquid gasket from the factory? It looks like it was put on using RTV, just checking if that is normal.

 

[CoronaRaptor]

Well, there is only 2 ways for the diff to overfill with oil.

1) the truck was on it's side when the last tech filled the diff.
2) there is water in the bottom of the diff and your inspector just dumped the oil out. Oil floats on water.

 

[CoronaRaptor]

Got a mystery for yall, maybe you guys have seen this before. I took my 19' in for a state inspection to a local shop, and had them just check the front and rear diff fluid while it was there. Apparently when the tech pulled the fill plug on the front diff, fluid started coming out of the fill port!

The reason I had them check the diffs was because I had been through some high water, and just wanted to see if there was any indication of water in the diffs. Also, a while back, I had to replace a front axle assembly (long story), and when I pulled the original out, I lost some fluid, maybe 8 oz or so, so I was thinking the front diff was going to be low.

So how can a front diff make fluid? About the only thing I can think of is that it was overfilled from the factory. The tech said there was no indication of water in the fluid.

Couple additional questions for you guys on the subject of the front diff. If the front of the truck is level, and you pull one of the axle assemblies out, I was under the assumption that it should be full enough that fluid gets to the seals, so losing some fluid may be normal? Also, is the front diff cover put on with a paper gasket or a liquid gasket from the factory? It looks like it was put on using RTV, just checking if that is normal.

How would the tech know if there was no water in there if he didn't pull the cover off? Did he siphon all the fluid out and refill it for you? Just asking....

 

[Muchmore]

How would the tech know if there was no water in there if he didn't pull the cover off? Did he siphon all the fluid out and refill it for you? Just asking....

Probably looking for the chocolate milk look. If they set long enough after being driven you are right on, the oil/water will separate back out and you would never know. If you check it while it's hot right after driving it will still have that chocolate milk look to it along with metal flake if your really unlucky

 

[Ruger]

Probably looking for the chocolate milk look. If they set long enough after being driven you are right on, the oil/water will separate back out and you would never know. If you check it while it's hot right after driving it will still have that chocolate milk look to it along with metal flake if your really unlucky

We're talking about the FRONT differential, here. The fluid/s in the front differential won't be hot or stirred up if the truck was recently only driven in 2HI - which is likely if he just drove it to the shop.

I recommend a complete draining of that front differential (siphoning out the fluid won't be thorough enough, I bet) and starting over with fresh fluid.

 

[TravisHTX]

Good point on the diff not mixing it up when has not been recently switched out of 2hi, I did not think of that. I do not know if the tech did that, or what he did to confirm if there was water at the bottom of the diff. I would agree with yalls assumption that they were probably just looking for the chocolate milk. I got charged a whooping $0 for them checking the diff fluids, so I would imagine they probably stopped after fluid came out of the fill port. I would imagine the tech took the vehicles age into consideration and figured it was probably better for warranty services to do any more digging past what he discovered because obviously something is wrong.

I have been needing to schedule an appointment with a dealer to get that software update applied in regards to the cam phaser, so I will just add this to the list. I had been meaning to check the diff levels for a while, but you know, life and being lazy kept getting in the way.

It just had me baffled on how the level could increase. As far as I am aware the only way for the level to increase is either water got in, or it was overfilled from the factory. If my diff was filled at an angle, then I would imagine more of you guys would have reported overfilled diffs from the factory.

 

[GCATX]

Click it in 4wd and drive a minute or two and pull the plug yourself. No way I'm waiting an hour at the dealer to do that. Or just get one of these see through diff covers.

 

[TravisHTX]

ha! Hopefully that’s not the same plastic that Home Depot buckets are made of. Leave one of those things in the sun for a month or two and they shatter to a million pieces on impact.

 

[MRV99]

That diff cover is not a real diff cover. That is what Banks used for demonstrations to show people how the aftermarket diff covers were actually causing more harm then good. That is not mention for actual duty.

 

[CoronaRaptor]

Good point on the diff not mixing it up when has not been recently switched out of 2hi, I did not think of that. I do not know if the tech did that, or what he did to confirm if there was water at the bottom of the diff. I would agree with yalls assumption that they were probably just looking for the chocolate milk. I got charged a whooping $0 for them checking the diff fluids, so I would imagine they probably stopped after fluid came out of the fill port. I would imagine the tech took the vehicles age into consideration and figured it was probably better for warranty services to do any more digging past what he discovered because obviously something is wrong.

I have been needing to schedule an appointment with a dealer to get that software update applied in regards to the cam phaser, so I will just add this to the list. I had been meaning to check the diff levels for a while, but you know, life and being lazy kept getting in the way.

It just had me baffled on how the level could increase. As far as I am aware the only way for the level to increase is either water got in, or it was overfilled from the factory. If my diff was filled at an angle, then I would imagine more of you guys would have reported overfilled diffs from the factory.

Hopefully it was overfilled, but that’s hard to do, not impossible.