The only 2015 F150's that have the 9.75" gear sets are the ones that have the heavy duty payload package. All the others have 8.8". That US Standard gear website is incorrect. I know for a fact that my truck has an 8.8" in it. The 2.7L does not offer the heavy duty payload package.

 

Why did Ford switch from Limited Slip to Non-Limited Slip differential? Which is better?

 

THe 2015 F150 comes in both.

If given only those two choices for street driving, I would choose LSD, but then again you might be forced into a different gearing that you don't want.

If given the extra choice of automatic locking rear axle, I choose (and did choose) that.

 

lol that is being debated in several threads, included the other active one.

Short answer, they feel they can get the same results in 2wd/daily commuting situations by using the TCS to control wheel speeds (some call it eLSD). In other situations, such as offroad, where traction needs to really be increased, the locker provides stronger results than a LSD would.

A lamens break down of the options:

open diff - 1 wheel drive (all the time)
LSD - 1.5 wheel drive (available all the time, but not in use all the time)
locked diff - 2 wheel drive (only at low speeds when required)

*in reference to 2wd scenarios

 

They Used a Lariat 4x4 (no FX4 pkg.), and set it to 4A mode and let the computer decide which wheels to drive. They had deep fresh snow (which is a blast), and not ice.

YouTube - 2015 Ford F-150 Off-Road Snowy 4X4 Review: Bashing through a Colorado Snowstorm:

 

They had fresh dry powder snow. They wouldn't be having fun in the same amount of settled wet snow.

I think the air dam would of stopped them in just a few feet.

 

I've driven F-150's with Limited Slip, and E-Lock. My 2 cents is that if you mostly stay on paved roads, and live in a place that gets snow in winter, the limited slip is nicer, b/c it's always working as you're spinning your tires on snowy roads.


When I use E-Lock, it's mostly preventative; boat ramp, driving on sand, or pulling someone out of the ditch, stuff like that. I don't think I'd ever engage it for driving on road in snowy/icy conditions.


I shut off traction control in deep snow, when I need to build momentum to push through the pile of snow that the county left me at the top of my driveway. Or for fun, because it's nice to spin the tires on snowy roads and fishtail for fun every once in a while.

 

I had the e-locker 3.55 in my 2013 XLT. I used it three times. All three were just because 'oh hey, i have this option'. And we do get snow here in metro Detroit, i just didn't use it. That truck was about $40k and this one is about $60k and some lawn parking is the extent of off road scenarios either truck would ever see.

I would suggest that if you are not first running, at a minimum, all-terrain tires that are designed for traction in less than a concrete jungle type scenario the locking rear diff is like a spoiler on a Prius. I'm not saying that it's bad to have, but like the spoiler the usefulness of it simply has its limitations.

Back to the topic of tires. I have noticed that in snowy conditions the wider Hankook tires on 20" rims this truck has under perform the the narrower Goodyear's (on 18") I had on the XLT quite a bit. Overall diameter of the wheel/tire combo on both trucks was very similar (nope, didn't measure) but, both stopping at a stop sign and then pulling away from it I have less traction on this truck that the previous one and the new truck has a shorter gear ratio.

I guess what I'm saying is that if you're running street tires in 4wd Low with a locked diff you just might be doing it wrong. I didn't let the rear axle guide my decision on this truck and so far I have been pleased with the non locking 3.31. ymmv

 

Oh and to comment on the traction control..... I disable traction control when in snow or on a wet dirt road where I have to get up and go pulling out into traffic. I'd rather be in control of the truck not moving due to loss of traction than me freaking out as the power cuts out while im coasting 90 degrees to a hoard of traffic that I was hoping to get past.

Traction control kicks in, I floor it and then realize I need to let off the throttle, I count the milliseconds as my life flashes before my eyes, I hope that I can get back on the throttle now, I cautiously do, truck seems to be under power again, I hear the horns honking as I finally get across both lanes. Or..... Tires begin to spin and I curse at all the stuff that may or my not be hitting the paint job as i back off the pedal and feel the tires grab and I get across the lanes smiling because I remember how fun it was to roast some tires back in the day. Something like that anyway.

 

The Elsd on the newer trucks makes them way more capable than the old rear only mechanical LSD. Just shut the throttle control off with one touch of the TC button, pr 2 quick taps to raise the threshold of intervention. If you need 100%, hold the TC button f0r 5 seconds, and go nuts. I've owned many configurations, the elsd at both ends is pretty amazing.