Flat Back Diff Cover - Failures 🤔

Originally Posted by 4WD
If flat back diffs made any sense … you would certainly see hundreds of them from OEM's of all shapes and sizes.
But we don't … Dozens of brands … all domed and tight to the ring …

Air entrainment means a percentage of oil is not available at the stress riser regardless of fluid capacity … so there is something to the standard shape of diff covers running tight to the ring and sending a concentration of lubricant to the concentration of stress … pinion, spiders, pins, etc … Splashing against the dumb stuff is what a flat back is good for …


Look for other videos. There are a few banks ones... one he has the domed cover that is clear, and it too has a lot of aeration.
 
Originally Posted by SavagePatch
Originally Posted by JHZR2
Wait, so now a Mag Hytec cover can cause damage?

Did I read that right?


Per Banks, yes.

But along with being a great researcher and developer he's also an amazing promoter. That's why I wanted the opinions and real world experiences of the members here.


He is neither and at best a charlatan prestidigitator fueled by a profit motive.

His entire methodology is fundamentally and fatally flawed, his analysis and conclusions are garbage and recommendations are worthless. He either doesn't have the fundamental grasp of gearing and tribology or he is deliberately skirting it.

And that's coming from a gear system design engineer under AGMA standards and has custom made gear drives ( Falk, Dodge, Rexnord, FLS, Ferry Capitan to name a few) by the hundreds for paper and mining applications.

Another reason to be careful regarding "online expertise" using only anecdotal information validated by " 3 blind men examining an elephant" techniques by people who are unqualified to make such decisions in the first place.
 
So you did not address the comparison of flat -vs- contour … why do the OEM's and many aftermarket companies not produce the flat back ?
 
I pointed out … if this xx % foam … better to confine the flow of fluids …
This time a 3rd party aftermarket cover

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Originally Posted by 4WD
So you did not address the comparison of flat -vs- contour … why do the OEM's and many aftermarket companies not produce the flat back ?


Because its non sequitur overall and not a contributing factor either way. (a placebo argument)- there is no comparison other than one allows for more volume than the other. As to "why", you would need to ask them. (most likely cheaper)

First, the problem has to be defined as it is being experienced and this was not done.

Is it aeration, cavitation, foaming or what- each one of those exist in gearing and each has a distinctly different set of causes and ways to address. You cannot make a proper diagnosis by "looking at the pretty bubbles".

You have to know the gear angles, pitches, contact paths, back riding etc. in order to know what stresses the gears impart into the oil and what properties the oil must have to accommodate them. ( in addition to loads and RPMs)

You adapt the lubricant to what stresses the gears induce- aeration ( in any form) is a result of some form of mechanical interaction affecting and overwhelming the property in the oil designed to mitigate it.

This requires a bit of FEM/FEA, thermography, calculating, VA and UT to get the data on the design and troubleshooting end. There's a lot that goes into a proper diagnosis and cure and none of it is a "look see" followed up by a "here's what I think" analysis.

Nothing he has presented shows me he has even attempted any legitimate analysis to any minimum degree to validate anything.

These techniques for dealing with these issues are universal and well known throughout industry and not made up for this post- when people ignore all that and just do "stuff and things" to appeal to peoples sense of "logical reasoning" as a basis of establishing a truth- that's often begging for trouble. ( the textbook criteria for being a "mark" in a confidence game)

What amounts to a "splash guard" ( or an oil galley if it directs pour) doesn't have a significant input on any of that is other things such as level, proper lubricant etc. are correct.

If this guy ever does a proper analysis with industry proven techniques then that will get a revision of his claims but not until then.
 
Originally Posted by 4WD
I pointed out … if this xx % foam … better to confine the flow of fluids.
Why?
 
Come on … it's the least "work" on the fluid to get it over the top to the ring and pinion interface …

You can slander Banks and offer your standard self promotion all you want …
but your use of placebo and cheap.? Never mind me … That means the OEM's need to feel good or only be cheap ?
That GT500 cover is not cheap.
 
Flat back gets lots of oil on the flat surface … does that surface need oil ? … you bought one ?
 
Originally Posted by 4WD
Come on … it's the least "work" on the fluid to get it over the top to the ring and pinion interface …

You can slander Banks and offer your standard self promotion all you want …
but your use of placebo and cheap.? Never mind me … That means the OEM's need to feel good or only be cheap ?
That GT500 cover is not cheap.



No, I stated facts that are widely known and in use globally for decades for every type of gearing that exists. ( there is no magic in a differential that makes those spiral bevel gears different than any other). None of it was made up for posting benefit or his detriment.

They are correct regardless of whether you or anyone "likes" them or not.

I would say the same thing if a Medical Doctor violated all known diagnostic techniques and practices and used chicken bones and tarot cards to diagnose an illness and recommend a treatment plan.

The fact this guy is a "hero" to some carries no weight with me whatsoever- when anyone goes off and makes claims like that and tries to pass it off as "legitimate science" then they can expect to be challenged by those who are legitimate experts in the referenced field.

I stated exactly why it is a placebo argument and you simply didn't like the answer- that is not a reflection on me or my credentials as much as it is a lack of any legitimate substance to your own position.

Also, the "fact" you cannot refute any of it and offer a different reasoned analysis is also telling. Just ad hom.

I drew no conclusion or made reference to anything an OEM may or may not consider and "cheap" is a dimensionless term.

Stage 1 Dunning-Kruger effect
 
There are two viscosity choices the OEM and owner make. Don't need all that other cause and effect stuff in this thread. … Oh, and about 5 companies supply the vast majority of these two grades.
Close enough at this point ?
Now we need to wind up with the least amount of parasitic loss to get the required amount of gear oil over the top where the ring and pinion meet. Banks is saying the same thing as OEM's … Flat back is not the best at doing that.
then he decided to cool the oil … no harm, no foul … but I'd probably not want those side scoops …
Nothing complicated or egregious here …
 
Originally Posted by 4WD
There are two viscosity choices the OEM and owner make. Don't need all that other cause and effect stuff in this thread. … Oh, and about 5 companies supply the vast majority of these two grades.
Close enough at this point ?
Now we need to wind up with the least amount of parasitic loss to get the required amount of gear oil over the top where the ring and pinion meet. Banks is saying the same thing as OEM's … Flat back is not the best at doing that.
then he decided to cool the oil … no harm, no foul … but I'd probably not want those side scoops …
Nothing complicated or egregious here …


If you are happy, I'm ecstatic for you.

You know what they say about the state equating to bliss, I would never dream of upsetting that balance with you.

However, there might be others who would benefit from a more detailed insight.
 
You are far from the only one who does FMECA's … you just like inserting that stuff where it's not needed.

After all the other work is done … you still have to maintain a viscous coupling to get the fluid over the top. … not sling oil against a flat surface …

Did you ever consider it's the minority that did none of this great work you enjoy touting ?
Those that produced what is in the title.
 
Originally Posted by 4WD
Flat back gets lots of oil on the flat surface … does that surface need oil ? … you bought one ?

I had them on my F-150 and F-250 (no longer own either of them), but and obviously the back of the cover is not the only place that oil is transported/transferred. I stand by my statement that Banks did not prove or disprove anything, there was no third party verified data to substantiate his claims, and that if flat back covers were that bad or were detrimental that by now, the world would know it.
 
Banks backed what OEM's have done millions of times … then he added cooling, that's really all.
One thing that tends to happen regardless of cover choice is something like Amsoil or Mobil 1 goes in … and funky break in oil gets dumped … and it's all the better for that.

Banks is not my hero as some might suggest … In fact, all he sold me was the idea that AAM and Dana know the business and my $400 can buy lots of good Delvac 1 …
 
Originally Posted by Snagglefoot
He also does a shameless pitch for Amsoil.
Which is probably the best thing he did during the entire series.
 
Originally Posted by 4WD
In fact, all he sold me was the idea that AAM and Dana know the business...
Based upon the issues that both have had in the past decade--Did the Dodge trucks not have axle issues with AAM and Dana is sucking wind terribly on the LSD axles in the Jeep Wranglers right now, it could be questioned how well they "know the business", but I get your point.
 
I think I will stay with the stock painted steel cover on my AAM 11.5 equipped 3500. Last fall I was grossing 33k at or near 100km/h highway speeds for some distance. IR temp gun put the diff at 168F right after the tow. Hmmm, i guess without the banks unit my diff is headed for an early death.
 
Originally Posted by 4WD
You are far from the only one who does FMECA's … you just like inserting that stuff where it's not needed.



Apparently not as much as you seem to like using acronyms that you obviously don't understand what they are and mean and inserting them in a tantrum where their misapplication is obvious. The correct term in this application would be an RCFA because we are dealing with a failure occurrence- the FMECA is a leading tool for design. Just FYI

I did insert that because you were in error and required correction so it was needed.

Originally Posted by 4WD
After all the other work is done … you still have to maintain a viscous coupling to get the fluid over the top. … not sling oil against a flat surface …



There's no "clutch" in a gear set nor stiction requirement so viscous coupling is not correctly applied in this discussion. This is a gearing issue. The clutch issue (where applicable) is a separate entity altogether as that basically allows for creep to relieve torsional stresses and is a different tribology scenario. ( even though both are frequently found in the same housing)

The fluid will ride in the teeth in volume for volute gearing and (depending on the leading contact patch angle of the helix) will determine the flow. This is a design parameter for initial damping along the pitch diameter then boundary lubrications along the engagement path. The fluid type/ level/ relative angle and RPM (assuming splash lubrication systems) will determine if the correct volume is present during the power transfer cycle.

Don't know what you mean by "all the other work done"- the oil "slinging against a flat surface" is a textbook cooling mechanism employed universally in gear systems where oil gets somewhat dispersed and starts cooling in the pocket then transfers heat to the housing so it can eventually wick away. This is the basis of setting a thermal imager to "high contrast" to use for lubrication PM to check the level and cooling of a gear box in service. It does serve a purpose.

Originally Posted by 4WD
Did you ever consider it's the minority that did none of this great work you enjoy touting ?
Those that produced what is in the title.



I consider what's presented by the presenter and weigh the conclusions against the analysis submitted. No evidence of any legitimate analysis using proper methods by qualified people presenting a properly reviewed synopsis and conclusion has yet to be presented relative to the claims.

If you have one, I would love to see it.
 
Originally Posted by blufeb95
Banks findings weren't that the flat backs cause failures, it's just that it causes excessive aeration of the gear oil which translates to lost fuel economy since you're wasting lots of energy whipping the fluid.


These things are difficult to discern with visuals but pretty easy with a motoring dyno with a Himmelstein torquemeter in the driveline.
Has anybody presented data like that?

If there were useful efficiency gains from relatively simple mods to the diff cover, I think OEMs would be doing it.
 
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