3.73 LSD question
 

Is the 3.73 LSD in a 2012 a real (conventional) LSD requiring the friction modifier in the oil, or is it that "simulated" type that uses the ABS sensors to apply the brakes on the slipping wheel?
Does anybody know?
Thanks a lot!

I doubt if the 2012 is any different than my 2009 (3.73 LSD).

Service refill capacity is determined by filling the axle to 1/4-9/16 inch (6-14 mm) below the bottom of the filler hole with the vehicle on a level surface.

Add 4 oz. (118 ml) of Additive Friction Modifier XL-3 or equivalent meeting Ford specification EST-M2C118-A, for complete fill of 8.8 inch and 9.75 inch Traction-Lok axles.

I have never heard of one that just uses the brakes, as the driver side axle still would not turn. It takes the clutch packs locking up to turn the driver side axle.

:-huh

I believe the ABS sensors are used in the FX4 locking diff when it is not locked, making it act like an LSD when unlocked.
There is a video on youtube somewhere showing it. I'll see if I can find it.
Why would the wheel on one side not turn when you apply the brakes on the other side? That's exacly what an open diff should do - transfer the power to the wheel that turns easier, no?

No. In an open diff, the non-drive wheel is not power driven at all.

Also, the brake pulses are part of the traction control system.

That is incorrect, I am 99.9% sure about that. Are you saying only one wheel is driven in an open diff? Why have a diff at all then? That makes no sense, WhiteBeast! This is not how a diff works.
In an open diff, there is no "drive" and "non-drive" wheel. Whichever wheel spins easier is driven. At least that's how I understand the principle of a differential.

not completely sure about the 12's ... but in the 11's at least, the 1-wheel spin control is part of the traction control system. 09-10, turing off the traction control also turns off the 1-wheel spin control. 11's (and i assume the 12's), turning off the traction control still allows the 1-wheel spin control to work.

the LSD has been almost completely phased out in favor of the e-locker. But as i understand, for the packages that offer the LSD it is just that, a clutch style LSD. and you still get the benefit of the 1-wheel spin control to boot.

they wouldn't offer "open" "LSD" and "e-locker" if they weren't all different.

Here is the youtube link to one of the vids. I think they call it "electronic LSD" or "1-wheel spin control" (same thing I guess). The principle they use with the ABS sensors makes perfect sense also.

Spin Control pt 1.mp4 - YouTube!

Nevermind, you're correct. I read a little more on it and I realize where I got that notion. When a tire comes off the ground in an off road situation, the one of the ground is going to spin and the one on the ground...nope. And that's my story of getting stuck as fluck with an open diff.

I think you are right. But still, they would not be all the same, even if the LSD was electronic. In that case, the "e-locker" would be equivalent to the "electronic" LSD when the locker if "off", with the addition of the locker option. So I guess it would be possible.
But I think you are correct, the 3.73 LSD that's required for the HD payload package probably IS a clutch type LSD. I was just trying to confirm that.

Yeah, if you lift one wheel off the ground with an open diff, that is the one that will spin, no power to the other. It's because that one spins easier (a lot easier, LOL, in that extreme example). It could be either wheel, there is no "drive-wheel".
The idea with the "electronic" LSD is to now apply the brakes to that wheel only (the one which is off the ground) until it is even harder to turn than the one on the ground. That would "trick" the open diff and shift power back to the wheel on the ground, the one with traction.

Or you can just drink a beer, and lock in your e-locker.

The only LS axle they offer now is HD payload axle with 7 lug wheels, and that's the only axle you can get. No open or E-lock available for the HD. I'm assuming they don't want to or can't make a special E-lock HD sized axle. Maybe the elock can't withstand that much tq when loaded with the high maximum capacities? Or it could be they sell so few HD's that they can't justify developing the E-lock axle for it.

So there basically is no clutch type LSD available except with HD payload, right? But it doesn't matter, I guess, since the new e-locker axles have the "1-wheel spin control" (= "electronic LSD").
Yeah, I wish that e-locker with "1-wheel spin control" would have been available for my 2012 HD payload F-150. Sounds like the best of both worlds.