Differential question.

Ok so I've been doing some googling and youtubing about different diff technologies. The optional front Torsen diff is an interesting piece of technology. My question is regarding the rear diff... when unlocked, does it basically behave like an open diff or something else?

While I haven't spent a LOT of time investigating it, mine seems to act like a limited slip... it has broken traction (power-on oversteer) making both left and right turns on slick roads. A regular open diff would just spin the inside tire in my experience.

Also, in the Ken Block burnout vid, you can clearly see two burnout marks once he rolls forward out of the smoke.

I'm pretty sure the rear is an open differential mechanically when unlocked, but the electric wizardry Ford uses applies the rear brakes to the spinning wheel which can allow the unlocked rear diff to mimic a limited slip in low traction situations.

BTW, I love the front Torsen and the rear locker. These trucks will go through virtually anything.

matt33 said:

I'm pretty sure the rear is an open differential mechanically when unlocked, but the electric wizardry Ford uses applies the rear brakes to the spinning wheel which can allow the unlocked rear diff to mimic a limited slip in low traction situations.

BTW, I love the front Torsen and the rear locker. These trucks will go through virtually anything.

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That's what I was leaning towards myself, but i'm only basing that on the fact that it isn't advertised as being anything else (other than the locking part of course) Typically if it was an LSD or Torsen it would probably be advertised as such.

jabroni619 said:

That's what I was leaning towards myself, but i'm only basing that on the fact that it isn't advertised as being anything else (other than the locking part of course) Typically if it was an LSD or Torsen it would probably be advertised as such.

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Ford has a special name for using the brakes to create a LSD. Can't remember what it's called though. Something similar to traction control. Idk if Raps have it but regular f150s do. There's not much a need for it since you can just lock the rear yourself in a Rap.

HankTheTank said:

Ford has a special name for using the brakes to create a LSD. Can't remember what it's called though. Something similar to traction control. Idk if Raps have it but regular f150s do. There's not much a need for it since you can just lock the rear yourself in a Rap.

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I'm curious because there's an off-road trail nearby with a pretty steep hill that my friends and I have been trying to summit, none of the vehicles we've used have a locking diff so I wanted to attempt it unlocked for a more "apples to apples" comparison. I don't have my Raptor yet but the adventure planning is well underway.

HankTheTank said:

Ford has a special name for using the brakes to create a LSD. Can't remember what it's called though. Something similar to traction control. Idk if Raps have it but regular f150s do. There's not much a need for it since you can just lock the rear yourself in a Rap.

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AdvanceTrac

mechanically its an open differential when unlocked. the braking system applies when slip is detected, forcing power to the other wheel via spider gears.

what would be the reasons they don't put a Torsen in the rear end ? Seems like it would do everything all the other controls do without the complication.

DANACO said:

what would be the reasons they don't put a Torsen in the rear end ? Seems like it would do everything all the other controls do without the complication.

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My best guess is durability. Everything I've ever read about differentials says that open diffs are the most reliable, longest lasting out of all the different technologies out there. Being that it's RWD very close to 100% of the time for most people, it would make sense to have the most reliable option back there.