AFE fabricated aluminum diff covers

3/16" aluminum doesn't sound strong enough for offroading. Might be ok for mall crawling.

I got a chuckle from their marketing-speak: "A dual purpose fill and calibration plug eliminates overfilling of the axle." — like every other fill plug on every other diff ever made in the last 10,000 years. :D
 
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OldBuzzard said:
3/16" aluminum doesn't sound strong enough for offroading. Might be ok for mall crawling.

I got a chuckle from their marketing-speak: "A dual purpose fill and calibration plug eliminates overfilling of the axle." — like every other fill plug on every other diff ever made in the last 10,000 years. :D
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It's 5000 series aluminum too. I've seen bumpers made of the same material peel apart on the rocks. There is no way this is suitable for a diff cover that needs to protect the gears inside. And then there is the $200 price tag.
 
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Engineered Adrenaline - isn't that Epinephrine? Do I need a prescription to order those covers?
 
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OldBuzzard said:
3/16" aluminum doesn't sound strong enough for offroading. Might be ok for mall crawling.

I got a chuckle from their marketing-speak: "A dual purpose fill and calibration plug eliminates overfilling of the axle." — like every other fill plug on every other diff ever made in the last 10,000 years. :D
Click to expand...

I agree on the aluminum. Not really on the fill plug. Way too many aftermarket diff covers come with the hole much higher than it should be. They are advertising that theirs does not come that way, which is good.

Still, I wouldn’t buy it just because of cost and the aluminum factor, but I think the marketing on the hole is fair.
 
machoheadgames said:
I agree on the aluminum. Not really on the fill plug. Way too many aftermarket diff covers come with the hole much higher than it should be. They are advertising that theirs does not come that way, which is good.

Still, I wouldn’t buy it just because of cost and the aluminum factor, but I think the marketing on the hole is fair.
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How does a diff cover manufacturer know how high or low the hole should be? In my case, the front and rear D44s have two very different pinion angles.
 
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machoheadgames said:
I agree on the aluminum. Not really on the fill plug. Way too many aftermarket diff covers come with the hole much higher than it should be. They are advertising that theirs does not come that way, which is good.
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With my LJ purchase a couple years ago, I'm new to solid axles. I've always thought that the reason the hole is too high is so that you can fill it easily when you rotate the pinion upwards. Too high is much better than too low. On my LJR, the only way for me to get enough oil in the diff so that the level is slightly above the bottom of the ID (so that the wheel bearings get oil) is to jack up the rear axle as high as possible, or find a hill and park pointing down, when I fill it.

I'm honestly asking if this assumption on my part that the oil level should be just above that ID is a bad one...

Edited to add: And judging from jjvw's near-simultaneous reply, I'm guessing that my assumption may not be so bad, after all.
 
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Fill the diff with the correct volume. The fill hole doesnt know where your axle is positioned, calibrated or not.
 
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tworley said:
Fill the diff with the correct volume.
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This never made sense to me, but, again, I'm a relative newbie to solid axles. If it's important to get oil to the outboard wheel bearings, would not the oil level in the axle be important? And if that is the case, and the volume changes when you rotate the pinion due to the pinion bearing's cavity moving, wouldn't the proper volume depend upon the pinion angle? Here:

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Maybe the change in volume [edited] doesn't matter is not significant?
 
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sab said:
This never made sense to me, but, again, I'm a relative newbie to solid axles. If it's important to get oil to the outboard wheel bearings, would not the oil level in the axle be important? And if that is the case, and the volume changes when you rotate the pinion due to the pinion bearing's cavity moving, wouldn't the proper volume depend upon the pinion angle? Here:

View attachment 427520

Maybe the change in volume [edited] doesn't matter is not significant?
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If we overfill, the diff has a tendency to spit out what it doesn't want up through the vent.
 
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jjvw said:
If we overfill, the diff has a tendency to spit out what it doesn't want up through the vent.
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I had read that on here some time back. What about underfill? How sensitive is wheel bearing lubrication to fluid level?
 
sab said:
I had read that on here some time back. What about underfill? How sensitive is wheel bearing lubrication to fluid level?
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I don't think the wheel bearings on either axle is lubed by the gear oil... only the carrier and pinion bearings...
 
sab said:
I had read that on here some time back. What about underfill? How sensitive is wheel bearing lubrication to fluid level?
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Wheel bearings are stupid. They get put in dry with some assembly grease, they may or may not get much oil depending on how fast you corner or how fast you go, and the only reason I can come up with why they don't die a horrible death more often is the little upset in the end of the tube holds just enough oil to keep them alive.

You can't overfill unless you want to build a return system on the vent. The reason they spit out the excess oil is the spinning axle shaft picks it up and slings it against the vent tube. Viscoscity being what it is has just enough capillary effect to hold the oil in the hose until more and more finally pump it out the end. The good news is that it self corrects and will eventually stop pumping it out. The bad news is the mess it makes.

The better question is how much oil in an underfilled diff gets slung into the tubes to make its way to the wheel bearings? I'm going to guess plenty because I've seen a lot of underfilled diffs, I've never seen a burnt up wheel bearing.
 
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sab said:
With my LJ purchase a couple years ago, I'm new to solid axles. I've always thought that the reason the hole is too high is so that you can fill it easily when you rotate the pinion upwards.
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You're a better engineer than that. There was no provision whatsover to set a fill hole height based on the vehicle being altered from stock.

That and the level was never set by hole height, always by volume.
 
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mrblaine said:
Wheel bearings are stupid. They get put in dry with some assembly grease, they may or may not get much oil depending on how fast you corner or how fast you go, and the only reason I can come up with why they don't die a horrible death more often is the little upset in the end of the tube holds just enough oil to keep them alive.
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I pondered that myself when I installed my RGA axles. I didn't notice the little upset you mention (my powers of observation pale compared to yours), but I did wonder how oil makes it all the way down the housing tube often enough to keep the bearings from burning up. Especially considering the long, straight drives through west Texas and New Mexico, where you could go hours without having oil splash to the ends of the axle tubes...

mrblaine said:
The better question is how much oil in an underfilled diff gets slung into the tubes to make its way to the wheel bearings? I'm going to guess plenty because I've seen a lot of underfilled diffs, I've never seen a burnt up wheel bearing.
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I agree - that is a mystery. My limited solid axle experience is not enough to count on. I did notice on my rig that the the DC driveshaft and pinion were rotated properly, but in doing so, the fill hole was below the bottom of the housing tube ID. I wondered if they filled the diff with the rear axle raised or not, but suspected they didn't (that would take effort and most shops aren't going to put forth such effort.) I then wondered how the wheel bearings survived for 40,000 miles if they didn't. I also noticed that the Barnett covers use the high fill hole Dana Spicer cover. The obvious reason was that the shelf they weld on would go right through the fill hole on the stock cover, but I also concluded that it would solve the "problem" of having the fill hole below the housing tube ID, so I saw those covers as a win-win.

Now I'm not going to worry about it. If you've never seen burnt up wheel bearings with an underfilled diff, that's good enough for me!
 
sab said:
I pondered that myself when I installed my RGA axles. I didn't notice the little upset you mention (my powers of observation pale compared to yours), but I did wonder how oil makes it all the way down the housing tube often enough to keep the bearings from burning up. Especially considering the long, straight drives through west Texas and New Mexico, where you could go hours without having oil splash to the ends of the axle tubes...
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The 6-700 RPM that ring gear is turning is moving a lot of oil around. I suspect that is how most of it gets into the tubes. Drain back is likely the bigger issue.
 
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