Do Diff Covers Work Or Are They Just Bling?

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Originally Posted by hatt
Originally Posted by 02SE
Originally Posted by hatt
Neat. You have a pic of the cover?

The only factory aluminum covers I've noticed were on Nissans. I just figured they were swag like a chrome exhaust tip. They certainly aren't heavy haulers like a ton dually diesel.

Edit. I found a pic. Looks like the exact shape of steel covers. Aluminum with a lot of fins. I'm sure that does cool better than a stamped steel cover.


The problem with the Titan is that when it came out, it had a Dana 44 with a stamped steel cover. The Dana 44 was arguably undersized for the application, and when people towed, the diffs would occasionally overheat and self-destruct. So Nissan put an Aluminum diff cover on for better heat dissipation.

Weird. GM has used the 10 bolt rear for decades without major issues.


The GM 8.5" holds more gear oil than a Dana 44 8.5". Dana's in general call for quite a bit more bearing preload as well.....Especially the carrier side bearings!
 
The 337 degrees sure sheds light on Ram's recommendation the gear oil be changed every 10,000 miles under "severe service".

Will enjoy seeing the results. It's mid-September now, so results should be along soon.

What's really interesting is the interior design of the Ram's factory finned aluminum diff cover. Seems to back up a lot of what Mr. Banks has to say about the interior shape engineering:

[Linked Image]
 
I was just watching a video featuring a clear differential cover, and I'm starting to see that Gale Banks really is onto something here. In watching the video, the channel for the rings gear moulded into the rear cover definitely appears to be keeping the gear oil focused on the gear ring.

Those little "dams" or "fins" inside of the cover wod likely be there to move outlying hear oil toward the gear ring as well.

I am definitely starting to see how having a large cavity behind the ring gear could be to a detriment of ring gear lubrication. Without that channel, there is no guide for the lube. It's free to sling off as much as it wants, and it doesn't appear that there would be anything to really aid in the gear oil either finding it's way onto the ring gear, or back to the bottom of the case.

All theory. Awaiting test results.
 
Originally Posted by DoubleWasp


Those little "dams" or "fins" inside of the cover wod likely be there to move outlying hear oil toward the gear ring as well.




They direct oil to the carrier bearings.

There are all sorts of methods used to control where oil (motor and gear) goes in the racing vehicles I consult on. It's reassuring that the FCA Engineers also have an understanding when designing that OEM finned aluminum diff cover.
 
I can see that. I haven't done any cool new covers for my axle. But I think I'm going to order that cover for my Rams now. Seems like a really trick piece, and my local dealer can get them for me cheap.
 
Thanks hatt, Did anyone hear that hammering noise after the fluid got aerated? I will refrain from stating anything else as it may not sit nicely with the Mag-Hytec crowd.
 
Originally Posted by DoubleWasp
Un. Freaking. Believable.

I get the feeling that some lawsuits are going to be slinging Banks' way very soon.


Good luck to those who do. The videos are his best defense. If I'm on a jury and watch them, I'm pretty convinced he's right. They'd have to prove him wrong. Bet they couldn't.
 
I hope he'll run the dyno test with the OEM finned aluminum diff cover like I have, and is used on newer, higher GCVWR versions of this AAM 11.8 axle.

I'd say he was right in his suspicion of those aluminum, flat-backed aftermarket covers.

Yep, I heard the hammering sound too.
 
Originally Posted by DoubleWasp
Un. Freaking. Believable.

I get the feeling that some lawsuits are going to be slinging Banks' way very soon.

It appears Banks' points are pretty solid. OEM designs give the oil a path to follow instead of churning it into the cover. Then you add more oil to make the problem worst.
 
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I'm curious as to the 75w90 gear oil on a big dually like that. I always thought 75w140 was more likely to be specified for high load or towing applications. My Jeep's Dana 44s, which are extremely light duty, specify 75w140 if you tow.
 
80w140 in my GM HDs, as 75w140 barely makes the 140 grade and is equivalent of putting 0W50 in your engine.
I fill to when I can touch the fluid with my pinky (finger that is), or about an inch below the fill plug.
Drain and fill plugs require a square 1/2 inch drive.
 
Don't get me wrong. I am in no way saying that Banks does not have his ducks in a row. This is probably the best test of diff covers' capabilities that will ever be done. Maybe the only in-depth testing that has ever been done.

After watching his other videos, I'm actually convinced that suits will NOT be filed. He seems to have absolutely no problem calling manufacturers out by name and putting their stuff to unbiased testing to prove he did his research and made his stuff better, the right way.

I was just watching his Cummins 6.7 air horn shootout, and his products definitely slay the competition easily by superior design. I haven't done a whole lot to my trucks yet, but I sure will be considering Banks first.

I hope he does do a test on the AAM finned cover, since he is using a Ram for his test bed.
 
Originally Posted by hatt
Another video. Not the results video.
I like Banks and have always thought his company made good products, but we should unpack what he is saying. He makes the point that aeration causes heat--he repeats this ad nauseam in the video. Point of fact is that aeration happens regardless of cover design--his clear OEM cover demonstration in one of his previous videos shows that as do plenty of other videos. Is he suggesting the aeration generates more heat than towing? He then suggests the front pinion bearing will not be properly lubricated by using a "flat back" cover? Seriously?

Here is what I know. My 2010 FX4 had a Mag-Hytec cover on it from the first OC, I had it for 158,000 miles of which at least 45% of those miles were spent towing 8-9K pounds in the mountains and in temperatures up to 117F sustained. I never had a single issue with my axle, the UOAs were perfect and showed a normal wear trend--heavy at first and then less wear metals per mile even with longer OCIs.

You are free to draw your own conclusions from Banks' "testing", but I, on the hand, will take the actual use of the cover over a 5 year period of varying usage, over a 10 minute YouTube video which proves nothing.
 
I'm pretty sure Banks already knows the test results will back up his thinking. He didn't do all this to post the results: "oh yeah I was totally wrong in those four videos I posted."
 
Originally Posted by hatt
I'm pretty sure Banks already knows the test results will back up his thinking. He didn't do all this to post the results: "oh yeah I was totally wrong in those four videos I posted."
The ultimate question is what is he going to prove? If "flat back" covers were so detrimental to axle longevity (if that is his point and it seems to be based upon his stating they do not lubricate the front pinion bearing adequately), with the internet amplification that happens today, this would be a widely known issue. I can only speak to my own experience and it does not match his in the slightest. I am certain that if Mag-Hytec covers were SO bad that I would have destroyed my axle with the towing that I did--but that did not happen. Not sure what he is trying to prove, but I am not sure that he is going to prove anything.
 
Because your diff hasn't blown apart doesn't mean the aftermarket cover is offering longevity benefits or even as good as OEM. That sounds like the xW-20 guys.
 
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