diff cover question .

[powershooter]

i am going to build myself a larger steel diff cover , are there any type of oil deflectors in there to help with oil sling or are they just a cover ? i am referring to the aftermarket ones that hold more oil and are bigger .

[Herb]

Don' believe they have a oil deflector. Here is a picture of a MAG-HYTEC.

http://www.mag-hytec.com/differential.htm


I know alot spending $$$ on those aftermarket diff covers, holding that extra 2 qts or so of oil is good, though IMO personally, I dropped my rear diff at about 4,000 miles and made the switch to Amsoil Severe Gear and done with it. Though I like the look of the HYTEC cover.

[powershooter]

yeah the cost off those aftermarket ones are high, thats why i am building my own , its all free to me except for the oil . mine will have a fill and drain and maybe a sensor location .

[Herb]

Cool, like to see pictures when you done. :cool:

[Nosparkplugs]

Good luck, PML makes a high quality cover for under 250 with shipping I have 12 months of exreme towing holding up great. Unless you are really good welding & metal fab, thats a huge undertaking, not to mention risk of catastrophic gear failure.


http://www.yourcovers.com/

[powershooter]

yeah, i am going to do my homework on it then build it . i work in a large fabrication building and have access to every thing needed includeing a full machine shop . it will be a slow process , but worth it i think .

[johns4dor]

Powershooter,
The factory covers are made with the shape they are to keep the small amount of lube in the diff moving to the proper places. A friend of mine who has been writing tech at Four Wheeler and other 4x4 mags for about 40 years says the diff manufacturers tell him that they are shaped that way for a reason, oh well. The larger aftermarket covers, as Herb stated, have no internal baffles. The PML and Mag-Hytec are both well made procucts. I personally prefer the Mag-Hytec: 1. because of the o-ring sealing, and all plugs(drain, fill, sensor, dip-stick) are included in the base price. 2. because it is larger, 3 Qt. increase(6 total) compared to 1.5 Qts. for the PML.
Be sure to run Amsoil Severe Gear 75W-140 in your Fords rear Diff.

[johns4dor]

Powershooter,
I just looked at the picture of your bracket for the By-Pass Filter. Obviously you won't have any problems fabricating your own diff cover. Very nice work, and a whole lot of thought in it. When I build a bracket I look at 3 things: 1. Is it convenient? 2. Is it strong enough? 3. Is it blocking anything else? You apprear to have accomplished all of those with your By-Pass bracket.

[powershooter]

thanks, it was a pain in the but . however i do enjoy a good challenge .:D

[Diesel Engineer]

Something to keep in mind: extra fluid capacity is generally beneficial, especially in high heat, high load conditions, however in cold weather conditions it can potentially also be detrimental under certain cold and extreme cold conditions if the gear lube gets too cold and cannot reach proper operating temperature ranges.

During my engineering career at Ford we had an issue with trucks that were getting shipped to cold winter weather climates, and especially extreme cold climates such as AK. Gear lube has EP chemical additives (Extreme Pressure) and what they do is prevent metal to metal contact on the gear teeth. If you have ever looked at a ring and pinion and see how they are shiny, that is, in part, the EP additives embedded in the microstructure of the metal and what it does is allow the EP additive to help prevent gear tooth wear under loading. If you look at the gear teeth under a powerful microscope it is actually millions of peaks and valleys and the EP additives embed in the valleys of the steel and fill the voids in order to help prevent wear on the face of the teeth.

The problem the differentials was experiencing was that due to the extreme cold the EP chemicals were not reaching the appropriate temperature to become activated and effectively prevent the metal to metal contact. This was one of the reasons Ford changed to 75W-140 synthetic gear lube in the rear axles of all Ford trucks so that superior protection and performance would be achieved from extreme cold (as well as extreme heat conditions). The other reason was for heat reduction in hot weather high temp-high load conditions and increased durability of the axle and differential components. Note that this was achieved without the need to increase gear lube capacity. Ford tests vehicles and components under extreme severe durability conditions at a specialized test track (as well as laboratory testing) for hundreds of thousands of miles. This is not equivalent to average customer on-road or off-road mileage driving. It is much more severe.

Aftermarket differential covers that increase gear lube capacity are generally helpful and beneficial, however I do recommend adding a thermocouple probe and quality gauge (such as Auto Meter) so that you can monitor the temp of the gear lube.

I would also recommend purchasing one from a proven manufacturer, such as Mag-Hytec, for example, that has proper design, engineering and testing experience to ensure proper function. Improper design, overfilling, underfilling, sealing, or cavitation for example can cause issues in a cover that you fabricate. Mag-Hytec makes quality products and I would recommend purchasing theirs vs. attempting to fabricate your own. Dave

[johns4dor]

Dave,Thanks for your input on this thread, very informative and educational. You really bring up a great point of thought about the cold as regards where one lives or operates the most. Because of his discussions with the Engineers from the differential manufacturers, my friend from Four Wheeler Mag does not believe the stock cover should be replaced, that and the fact that he lives in Montana and most of his off-roading is slow and difficult. As he told me in a conversation a while back, the cover is shaped the way it is to keep the lube where it needs to be to protect the assembly.

[Ken's PS]

Dave:
Excellant write up and very informative. Most people order these from us for the cooling aspects they receive, maybe thats why I haven't sent any up to Alaska ;)

[Herb]

I just would like to say I know Kenny from Kens Performance Solutions, I have purchased all my performance products from him for my last CTD, he goes out of the way for his customers and always there for help and a great guy. :cool: Anything I will need for upgrades for my 07 6.7 I will be contacting Kenny.

[Analyst]

Dave - your insight & info is stellar. It's easy to see that you've dealt with real engineering based on real wear and failure analysis, and real data.

I don't have your depth in drivetrain lubrication, so I want to check myself a moment. I've always thought the biggest benefits of a larger capacity diff cover are in heat control through larger fluid capacity and greater external cooling surface area. And some of those aftermarket cover designs - especially ones specifically targeted for rock-crawling - definitely stiffen the diff housing. However, for towing 10,000 lb+ loads up long grades at full power in warm/hot ambient temperatures, it seems like those aftermarket-diff-covers offer thermal advantages that help keep the maximum and average operating temperatures of the fluid, gears and seals down in a range that will give long life. I think that's what you're saying, right?

A couple of questions:
1. The data - and real-world experience - indicates that AMSOIL diff fluids produce much lower operating temperatures than most other lubricants. But at the same time, AMSOIL fluid appears to handle much higher operating temps than "standard" gear lubes. So for "hot-shot" haulers and other people towing trailers cross-country with an aftermarket diff cover and temperature gauge, what is an ideal maximum temp target for the diff fluid, in your estimation?
2. Do you recommend two different max operating temperatures based on petroleum vs. Amsoil gear lube?