Installed my Mag-Hytec today

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Installed the cover today and refilled it with one 4oz bottle of Ford friction modifier and 4.5 quarts of Amsoil 75W-140 Severe Duty oil. I thought it held 5 quarts, but I think that is filling it to the upper dipstick mark.

We filled it through the factory hole to a point then switched to the dipstick hole. With the oil between the marks on the dipstick the oil is above the factory fill hole.

This OC was Ford synthetic 75W-140 and it had 56,600 miles on it (I changed it initially at 13,300 to remove any break-in metals). The front differential, transfer case, and transmission are next.

The Amsoil seemed to be thinner than the Ford oil and quite a bit thinner than the old Ford oil. I will be sending the Ford oil out for a UOA and I will post the results when I have them. I am sure this is a "seat of the pants" assessment, but there feels like less drag on the powertrain. It is CERTAINLY going to make maintenance much easier in the future.

Thoughts and comments always welcome!

Here are some photos of the internals and the cover installed:


fx41.jpg



fx42.jpg



fx43.jpg



fx4pinion.jpg



fx4spider.jpg



fx4maghytec.jpg
 
Originally Posted By: dailydriver
Every time I see one of those covers, or hear about someone installing one, it BURNS me that they do not make one for my axle!!
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That's because you need a Ford rearend!!! That GM one is junk! LOL
 
Originally Posted By: Bluestream
Ford recommends the fluid level be 1/2 inch below the (Ford) fill hole

Does that apply when an aftermarket cover is installed--especially when this one has a dipstick?
 
Why did you install the friction modifier? Looks like an open diff to me, so no FM is needed. This is what a Ford Limited slip looks like. You can see the Z-shaped preloads spring and the clutch plates. Your truck may have electronic traction control but that is controlled by the antilock brake system, not in the diff

Have the same covers on both my Ford axle (though they are 10.25 and not 9.75 axles) and love them. Go back and check the magnetic dipstick for metallic "fuzz" periodically.

The Amsoil seems thinner because being a PAO base, it flows better and most any temp, so "feels" thinner too.

Mag-Hytec wants you to fill to the top of the dipstick, contrary to the axle mfr's recommendation. I had a talk with the designer of the cover about that and he was adamant that the extra oil floods the tubes and cools and lubricates the wheel bearings better. He also claims it results in fewer axle seal failures. I tend to disagree but because I wanted to observe what effects his way may have had, I did it his way for several thousand miles. No ill effects. Nor any positive ones. I monitored oil temps both at the M-H level and Ford's level and didn't see a difference (sometimes high oil levels result in higher oil temps). I have ended up doing the same thing you did... midway between the marks.

TLLR.jpg
 
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Actually, I might be mistaken. The pic above is not a 9.75 LS. The 9.75 does not have the preload spring. I can't see the ring gear side, but the side of the carrier I can see, I don't see clutch plates behind the side gear. Here is a pic of a TrueTrac (left) and 9.75 LSD I shot some years back.You can see the clutch plates below the side gear in the carrier.

LSLR.jpg
 
Originally Posted By: Jim Allen
Why did you install the friction modifier? Looks like an open diff to me, so no FM is needed.

I did this based what Ford did at the 13,300 OC, the OM states to use it, and the many recommendations here. I will assume that no damage is done if I do not need it since Amsoil states the oil mixes with conventional oil. The ELD has a switch to engage it as well, but the axle "acts" like a locker because both tires roll in the same direction when off the ground.

Originally Posted By: Jim Allen
The Amsoil seems thinner because being a PAO base, it flows better and most any temp, so "feels" thinner too.

Good to know that it was not my imagination and that perhaps the "oil drag" may not be as bad as the Ford oil. For the few miles that I drove it tonight it "felt" different, but I am also skeptical about seat of the pants assessments.

Originally Posted By: Jim Allen
Mag-Hytec wants you to fill to the top of the dipstick, contrary to the axle mfr's recommendation. I had a talk with the designer of the cover about that and he was adamant that the extra oil floods the tubes and cools and lubricates the wheel bearings better. He also claims it results in fewer axle seal failures. I tend to disagree but because I wanted to observe what effects his way may have had, I did it his way for several thousand miles. No ill effects. Nor any positive ones. I monitored oil temps both at the M-H level and Ford's level and didn't see a difference (sometimes high oil levels result in higher oil temps). I have ended up doing the same thing you did... midway between the marks.

I waffled on this one quite a bit as I was worried about the level being somewhat higher than the seals, so I opted to go halfway on the marks. I am guessing that if I had used the entire 5 QTs it would have been at the top mark on the dipstick.
 
Originally Posted By: Jim Allen
Actually, I might be mistaken. The pic above is not a 9.75 LS. The 9.75 does not have the preload spring. I can't see the ring gear side, but the side of the carrier I can see, I don't see clutch plates behind the side gear. Here is a pic of a TrueTrac (left) and 9.75 LSD I shot some years back.You can see the clutch plates below the side gear in the carrier.

I did not post all of the pictures that I took. Does this help?

ringfl.jpg



ring2ol.jpg


ring3u.jpg
 
Looks very nice sir. Do you have just under 70,000 on the truck then? I bet you've been enjoying every minute of it!
 
Originally Posted By: panthermike
Looks very nice sir. Do you have just under 70,000 on the truck then? I bet you've been enjoying every minute of it!

Many thanks. Yes; I have 69,900 miles on it and it has been great thus far.
 
Originally Posted By: 2010_FX4
Originally Posted By: Bluestream
Ford recommends the fluid level be 1/2 inch below the (Ford) fill hole

Does that apply when an aftermarket cover is installed--especially when this one has a dipstick?


AS mentioned Ford doesn't care what type of cover you have, they recommend 1/2 inch fluid level below their fill hole. Will it do any damage to go higher, I have no idea.

Why the friction modifier? It does no lubricating and should only be used when you experience clutch plate chatter. I don't see any clutch plates on your unit.

What axel code is shown on your door sticker?
 
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2010FX4: Decoding the part number on the carrier, yeah, you have the Electronic Locking Differential, which is NOT a "Limited Slip Differential" and does not use a friction material/clutches. Therefore, according to the info I have, does not require a friction modifier. It's a simple mechanical locking device, with a cam ring that locks electromechanically.

The purpose of the friction modifier is to reduce the clutch plate chatter in a limited slip differential. The plates have a friction surface, kind of like brake or clutch linings, or more closely, like the clutch plates in an automatic transmission. The idea behind the FMs is to get them to release smoothly. The downside to FMs is that some have very low oxidation resistance, so in high oil temp situations, it can break down at a faster rate than the gear oil and causes the gear oil to oxidize faster because the anti-oxidant additives in the gear oil are forced to work harder. I haven't made a deep study of this but there are organic FMs and synthetic FMs and the organic ones break down faster. From what I understand, the Amsoil product is one of the better ones, so if you used that, you are probably better off. The other types are fine too, certainly in the short run. Long term is where there could possibly be issues but since you are using a top notch gear oil, I seriously doubt you are going to see any trouble. And if trouble came, it would come to someone who runs blisteringly hot gear oil temps often and it would simply be a somewhat shorter life of the oil. Someone who is up on maintenance as you are isn't going to be caught by surprise. The first sign would be a dark color and a bad sorta burnt smell. Somebody in the biz recently let me have a whiff of some gear oil he claimed failed due to excess FMs in the oil. It was dark and smelled REALLY bad. I only have his word on the situation but added it to my "to be verified" file.

I haven't had time to research more on FM limited slip additives. Perhaps Mola has some insight. Anyone else?
 
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I am installing one of these covers this weekend. My truck is supposed to have the LSD gears (non electronic). I will take pics and we can compare them to the OP's pics. I plan on using M1 75w-140 to replace the FF.
 
Originally Posted By: Jim Allen
2010FX4: Decoding the part number on the carrier, yeah, you have the Electronic Locking Differential, which is NOT a "Limited Slip Differential" and does not use a friction material/clutches. Therefore, according to the info I have, does not require a friction modifier. It's a simple mechanical locking device, with a cam ring that locks electromechanically.

The purpose of the friction modifier is to reduce the clutch plate chatter in a limited slip differential. The plates have a friction surface, kind of like brake or clutch linings, or more closely, like the clutch plates in an automatic transmission. The idea behind the FMs is to get them to release smoothly. The downside to FMs is that some have very low oxidation resistance, so in high oil temp situations, it can break down at a faster rate than the gear oil and causes the gear oil to oxidize faster because the anti-oxidant additives in the gear oil are forced to work harder. I haven't made a deep study of this but there are organic FMs and synthetic FMs and the organic ones break down faster. From what I understand, the Amsoil product is one of the better ones, so if you used that, you are probably better off. The other types are fine too, certainly in the short run. Long term is where there could possibly be issues but since you are using a top notch gear oil, I seriously doubt you are going to see any trouble. And if trouble came, it would come to someone who runs blisteringly hot gear oil temps often and it would simply be a somewhat shorter life of the oil. Someone who is up on maintenance as you are isn't going to be caught by surprise. The first sign would be a dark color and a bad sorta burnt smell. Somebody in the biz recently let me have a whiff of some gear oil he claimed failed due to excess FMs in the oil. It was dark and smelled REALLY bad. I only have his word on the situation but added it to my "to be verified" file.

I haven't had time to research more on FM limited slip additives. Perhaps Mola has some insight. Anyone else?

Thanks Jim! Good to know, but a bit disappointing as well that Ford also used the FM on the original OC at 13,300. I simply followed their lead and the Owner's Manual. Not that I am concerned about the $6.50 for the FM (which was Ford brand BTW), but that the Amsoil Severe Duty oil would have been better off without it. I guess 4oz added to 144oz of gear oil (as opposed to 88ozs) would have less of an impact though.

Not to worry, though, the Mag-Hytec will make it infinitely easier to sample the oil and should something go awry, changing it is even easier.

It is a bit strange how the axle "seems" to be LSD (even without the locker)--especially when both wheels are off the ground and both turn in the same direction when rolled. In one of the photos there does seem to be some disks beneath one of the gears. Obviously, the codes on the carrier tell the real story though...
 
Originally Posted By: Bluestream
AS mentioned Ford doesn't care what type of cover you have, they recommend 1/2 inch fluid level below their fill hole. Will it do any damage to go higher, I have no idea.

This will not be a problem and since I placed the fill halfway between the marks on the dipstick, it is not THAT much over full.

Originally Posted By: Bluestream
Why the friction modifier? It does no lubricating and should only be used when you experience clutch plate chatter. I don't see any clutch plates on your unit. What axel code is shown on your door sticker?

As noted in another post, I simply followed Ford's lead from the OC at 13,300 and the information in the OM. The previous fill was Ford synthetic and I plan to send it off for a UOA and will know soon enough how it fared through the last 56,000 miles.
 
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