Differential Cover, Which one is better?

CarbonSteel

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He had plenty of data to back up how the fluid was worked and he demonstrated how the shape of the cover affects the flow and coverage of the gears.

No other manufacturer is as open about the design process and how these things work. That's because they likely didn't spend nearly the effort to understand it.

Show me something from afe or anyone else that shows even a fraction of their design thought or even theory.

The Dana/Spicer cover still has a square area on it that bugs me. Honestly, I think ARB might have the best all-around design when considering both flow and protection of the bolt heads. They are just a bit more expensive.
What data? 10 minutes on a lift running a Mag-Hytec with a clear cover that he modified? Where is the hard core data points to substantiate his claims? Where is the viscosity loss he claims substantiated by data? Where is the third party objective, certified, and repeatable data to show temperature increases by use of a flat back cover? Did he show unquestionably the pinion gear was suffering from oil starvation or an increase in operating temperatures? I will give him this...he is a GREAT salesman and many folks bought into it...
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AnnDee4444

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Arterius2

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What did he prove aside from using the series as a pre-cursor/promo for his "new and improved" axle cover (which has to be the fugliest on the planet)?

I am concerned about the amount of oil in the D44 axles. 1.5QTs in the rear and 1.3QTs in the front is not a huge reserve. I would like to see 3QTs in both...
He proved that the stock cover from Dana Spicer was pretty well designed, and proved that you shouldn’t just buy *any* aftermarket cover just because it looked “cool” from the outside. I watched all of the videos and never got the feeling that he was pushing his product that hard, if anything, I felt like it was revealing and I would just hang on to my stock covers.

Now, if one understands basic physics, the science behind it makes sense. The shape of the cover has a significant effect on the fluid dynamics inside. And having poorly designed shapes such as oblique corners will invariably hinder its effectiveness, as for the fluid amount, I didn’t think aeration mattered much here, it was mostly to do with drag by having the bearings move more liquid than necessary all the time.
 
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CarbonSteel

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He proved that the stock cover from Dana Spicer was pretty well designed, and proved that you shouldn’t just buy *any* aftermarket cover just because it looked “cool” from the outside. I watched the all of the videos and I never got the feeling that he was pushing his product that hard, if anything, I felt like it was revealing and I would just hang on to my stock covers.

Now, if one understands basic physics, the science behind it makes sense. The shape of the cover has a significant effect on the fluid dynamics inside. And having poorly designed shapes such as oblique corner will invariably affect that effectiveness, as for the fluid amount, I didn’t think aeration mattered here, it was mostly to due with drag by having the bearings move more liquid than necessary all the time.
He did not debut his cover until the end of the series, so other than dissing everyone else's cover (at that point), I agree there was no pressure to buy his.

However, I never saw any objective, repeatable, and certifiable data that substantiated his claims. As I said before, had he not come out with his own cover, his observations would have been objective, but they are anything but now.
 

DanW

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I'm clearly not as hip as you, so i don't really know what you mean there. And I ain't your bro. Friend, sure, bro, no.

He explained pretty clearly the fluid dynamics and showed the negative effect of the flat back on the oil flow over the top to the pinion. That looked pretty obvious, to me.

You go from saying he is the ultimate salesman to acknowledging he wasn't doing a hard sell of his product through most of the videos. Ok.

I'm not rushing out to buy any of his products, but rather will probably stick with stock. If not, I'll be looking for a cover that most closely matches the OEM shape.

I think that guy has forgotten more than most of us will ever know. He's widely respected in the automotive industry, so there's that, too.
 

CarbonSteel

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I'm clearly not as hip as you, so i don't really know what you mean there. And I ain't your bro. Friend, sure, bro, no.

He explained pretty clearly the fluid dynamics and showed the negative effect of the flat back on the oil flow over the top to the pinion. That looked pretty obvious, to me.

You go from saying he is the ultimate salesman to acknowledging he wasn't doing a hard sell of his product through most of the videos. Ok.

I'm not rushing out to buy any of his products, but rather will probably stick with stock. If not, I'll be looking for a cover that most closely matches the OEM shape.

I think that guy has forgotten more than most of us will ever know. He's widely respected in the automotive industry, so there's that, too.
Still need the data and the data needs to be verified third party--not his in the quest to sell his products--why else did he do this series? Shining a flash light into a turning axle on a lift proves nothing and for all of his talk about aeration, viscosity loss, temperature increases, and the like, there was no data provided and how many millions of these covers are in use and have been for decades? If flat back covers caused those issues, we would know it by now.

Color me not impressed.
 

Hudson

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I bought the Metal Cloak. Mostly because I wanted a decent diff skid plate, front and rear. The metal cloak diff cover is cast iron, weighs a #$&@ ton. It’s like the Chuck Norris of diff covers.l If I accidentally back up into a rock, I feel sorry for the rock.

the skid plate for the rear will fit a range of diff covers but the skid plate for the front diff will only fit the Metal Cloak diff cover.

so that is what I bought. Price was 330ish for both covers and skid plates. Only bummer is I have to paint the diff cover as they come unfinished.
 

CarbonSteel

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So flat back covers/more lube is better? Why haven't the OEMs figured this out?
Anything provided by an OEM is typically balanced by three things:

1. Cost/profit

2. Service life

3. (and to a far lesser degree) Customer satisfaction

Based upon my experience in owning dozens of cars, I can easily attest which one trumps the remainder—profit. OEMs typically will not do anything more than meets a minimum threshold (whatever that is)…period. With that said, OEMs have installed increased capacity covers on some applications such as heavy duty trucks and the like.

My “horse” in this race has to do with the claims/suggestions that Banks makes without the objective, repeatable, third-party verified data as well as testing methodology to support them. A secondary issue is his overall opinion that flat back covers are “bad or add no value”. The reason that he is doing this is obvious—to state that his cover is “better”. Had he not produced a new cover, then his claims would have been objective versus a glorified sales pitch and this is why I say he is a great salesman—a few YT videos and taadaa, flat back covers are bad and Banks covers are good!

His premise and data would have been much more objective and valid had he used three axles in a controlled test for say 100,000 miles with about 25-50% of those miles towing and NOT a simulated test on a lift. The test components should consist of a:

1. Factory OEM axle

2. Factory OEM axle with a flat back cover

3. Factory OEM axle with a Banks cover


For example, (and I am paraphrasing so keep me honest), he states (and all of these infer or suggest a detrimental or negative situation in some way):

1. Flat back covers over work the fluid and cause excessive aeration.​

a. OK. Based upon what? A flashlight shined into the back of a Banks modified Mag-Hytec cover? There are incredible shearing forces at work within a differential and “working the fluid” happens regardless of cover design or fluid levels, after all, the ring gear is partially submerged in oil at all times.

b. If the fluid is overworked, then we can surmise that it leads to loss of viscosity or some other negative result. Where are the test results to show that viscosity loss occurred? Were they compared against factory OEM results?​

2. Flat back covers impede or interrupt fluid flow (or flow is not "optimal") over the ring gears.​

a. OK. Were temperature tests performed on the pinion gear in operation to determine that lubrication was insufficient? Were they compared against OEM results?

b. What about ring and pinion gear wear results?

c. What about viscosity results? Was the fluid overheated by the pinion gear that allegedly receives less lubrication due to the flat back design?​

3. Flat back covers increase the volume of fluid and this is not optimal for the bearings.​

a. OK. Were the bearings inspected and measured at zero miles and then again after the test?

b. Were they compared against OEM design and conditions?

c. Were temperature tests performed on the bearings and compared against OEM?

d. Did the increase of fluid also increase the service life of the fluid or the assembly in some way?​

4. Flat back (finned) covers do not improve temperatures.​

a. OK. Were the flat back temperatures compared against OEM temperatures in various operational conditions?

b. Were the tests performed with actual temperature sensors at critical points of the assembly versus pointing an infrared temperature gun at the housing?​

As I said before, without a certified testing methodology and a proper baseline set, all of these “tests” were nothing more than a glorified sales pitch for his new and improved axle cover. I have seen nothing since then to change my mind, but I am totally open to "eating crow" should the data present itself to substantiate his claims.
 
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InvertedLogic

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FWIW, in Part 3 of the series he does get into a few quantitative tests. Specifically addressing aeration measurement, and fluid temperature when towing up a standard grade with the 3 different covers.

I would also be interested in the UOA @CarbonSteel since Banks did not show one.
 

twisty

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