This does not look good

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Went to change fluid and pinion seal. To find this... what now? Is rust at all common? My assumption is that gasket either failed or wasn't installed correct at all. I scraped nothing from the face.

I'm way over budget on this thing. How difficult fix?
 

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TNBrett

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It’s obviously not good, but I don’t think it’s the end of the world. I’ve seen gear sets with rust pitting like that, that have still done lots of miles. It all comes down to what you’re planning on doing with the truck. If you’re using the truck every day for work hauling around 15k lbs of trailer, or dragging a 5th wheel RV across the country, I would recommend you fix it right, right now. But, if you’re driving 10k miles per year, mostly empty, or pulling only a couple thousand lbs, it’s not so critical. Assuming you’re in the latter camp, I would clean it up the best you can, put fresh oil in it and run it. In 500-1000 miles drain the gear oil again, and look closely for signs of metal. If it’s not too bad at that point, you’re probably going to be ok for quite a while. Maybe change the gear oil at every other oil change, just to keep an eye on things. The thing to keep in mind is that if things go bad, the most cost effective fix is probably going to be swapping out the whole axle with a good used one.
 

gnathv

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I’d drain the oil, wire brush and sand all I could, spray brake clean to wash it into diff case, clean out case and add new oil.
 

BrianX128

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Where is your axle vent hose thing? Awkwardly hanging down by a tire can do weird stuff on the highway in heavy rain.
 

aggiediesel01

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I too was going to suggest checking the vent line and or the actual axle vent. Down here, the rubber likes to dry out and crack and they frequently fall off but then the dirt daubers like to plug them up so it's easy to get moisture trapped inside. If the pinion turns nice and smooth with the correct backlash I'd run it for now and listen for howling. Probably should listen for and check the wheel bearings too to make sure moisture didn't get trapped there for too long but othewise it should be fine.
 

Noiseydiesel

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Just took a fast glance at your post. I had to chuckle at the "Way over budget".
My wife FINALLY admitted that buying a newer machine would have been less money.
Yeah, I started off with a 126K '94 F350 CC dually, 7.3 idiT with the E4OD for $7500 and now there is about $40K in front of that $7500.
One big secret is to keep your truck away from any shop. I had two incompetent shops play with mine and that added about. . . . $3,000 to the final bill.
Over budget? I remember a budget. That was when I was working and had no money.

Life is what happens while you plan for the future.
Work interferes with life.
Quit work and get a better life.

That only works if you can make heavy investments while you are working and have no budget.
So your not having a budget, I can understand. You have a lot of good advice here, change the oil, my diff's are running Lucas 75-140 a bit thicker but can stand a lot more abuse. True track in the rear and Elocker in the front. Best of luck!
 

CBRF3

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Went to change fluid and pinion seal. To find this... what now? Is rust at all common? My assumption is that gasket either failed or wasn't installed correct at all. I scraped nothing from the face.

I'm way over budget on this thing. How difficult fix?
okay first off replace the pinion seal and reseal the cover and fill with 75w-90 synthetic gear oil and add the friction modifier to the gear oil you have a trak lok which is a posi lock it has a clutch pack on both sides of the spider gears to me it looks like you simply had some moisture in there and it set for a while causing some slight rusting which is fairly normal our differential when they heat up and cool quickly draw moisture into them especially in cold climates when towing its simply the nature of the beast if you need further info on your trac lok dif like reoplacement clutch packs and such message me i can link you some that are around $75-$100 new and come with the friction disks and the slip disks from amazon.
 

TexasTruck

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Couldn't you hit that with a wire wheel and something like marvel mystery oil or kerosene to break it? It doesn't look bad at all.
 

CBRF3

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Couldn't you hit that with a wire wheel and something like marvel mystery oil or kerosene to break it? It doesn't look bad at all.
a simple hand held wire brush will remove it the thing he needs to worry about is making sure he adds the friction modifier and the synthetic 75w-90 gear oil and of course re sealing the pinion and cover.
 

subway

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while not great if they are not pitted on the mating surface it should not effect anything. like mentioned, clean it up as best you can with a wire brush, flush it out and fill. I would run it for a little checking the oil. if after a few hundred miles it looks a little dirty but no shavings, change the oil again and call it good.

while it does not look great, it can be rusty and putted all it wants on the outside of the ring gear. the gear does not mesh in that section.
 

Booyah45828

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I'll echo the others.

What you should do with this depends on how reliable it needs to be. If it's your livelihood, then rebuild the current unit or replace it with something good and used. Your timeframe for repair is also important, as plans change if you have to get this going immediately.

Most of the time when I see this in the shop, it's because of a plugged vent tube FWIW. Pinion seals, wheel seals, etc. can all be a source of water. Typically if the case cover leaks bad enough to allow water in, oil will come out. But even if a bit of water gets in there, it should boil off and evaporate out of the vent tube.
 
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