Hello all!

new to the F150. Just bought a brand new SXT 4x4 and love it. I do some minor off roading and have a question.

I was out on a soybean farm last weekend and noticed when my back wheels slipped they both spun WITHOUT me pulling out the **** to engage the locker.....

do these trucks have a lsd on them also? Does not sound correct to me but I’ve been so impressed with this truck it wouldn’t surprise me. I’ve done some searching on here but noticed the answers where to older models. Thanks in advance!

 

No limited slip if it has the elocker.
You didn't tell us what year so we may be confused.

 

its a 2020.

 

Then it is for sure an open diff until you engage the locker.

 

They should both spin, even with an open diff. Your truck is working as it should. Contrary to "urban myth", open diff always sends power equally 50 / 50 to both rear tires. There is no such thing as "sending power to the tire with least resistance". That myth has been so often repeated, that it has become (incorrectly) widely accepted. "One-wheel peel" does happen, but it's not because "power is sent to the wheel with least resistance", there's a whole other engineering reason. I've written a tutorial on how it all works if you'd like to see it, but not including it here to keep things simple.

Also, the truck has Traction Control, so to a degree you will see both tires moving in an attempt to gain traction as the traction control works its magic trying to get some grip.

 

No urban myth.

Power goes to both equally right up until one or the other has significantly less traction than the other. Or when cornering. I suppose in the OP's situation traction was equal between the 2 tires, or traction control was kicking in. If in a situation where one were significantly different you'll get all the power to the tire with the least traction. If power were going to both equally all the time it would be impossible to drive around a corner on pavement without doing serous damage to the truck

Traction control uses sensors to monitor different wheel speeds. If one wheel starts spinning the brakes are gently applied to that wheel forcing power to the other wheel on that axle. Remember, the one with the least traction gets the power. Applying brakes to the spinning wheel tricks the senosrs into thinking that wheel has more traction and the diff will send power to the other wheel. Traction control is basically using the same technology as anti lock brakes but using in a slightly different way

Before traction control we used the parking brake to do the same thing. If stuck in a situation where only one wheel was getting power, and the other had better traction you can gently apply the parking brake. It doesn't work as well as traction control, but will often result in getting power to the wheel on solid ground.

Traction control works great in snow, ice, wet grass, or light mud. But if in more extreme off road conditions turn it off. If you don't it is like trying to drive while dragging a boat anchor behind you. The truck will almost constantly be applying brake pressure to one or the other rear wheels every time one spins a little. This robs momentum getting through muddy spots.

Locking the rear diff does just that. It should only be used as needed for short distances preferably in a straight line or in extremely low traction situations.

 

It's urban myth. Torque goes equally to both rear wheels 100% of the time. No exceptions. What you're describing is the ability of the tires to rotate independently of each other around turns, which is the primary function of the open diff. The torque still goes equally to each wheel in a 50 / 50 split, all the time, 100% of the time. The details of how it works are in this post:

https://www.f150forum.com/f118/guide...control-416094

 

I'm not saying you are right or wrong. However the self fulfilling prophecy of directing the reader to another post is usually meant to have another "fact" about your case. Next time, try quoting another (different than the one you already referenced {yourself, in this case}) source.

In your reference, force, torque and power all mean something. They are not the same meaning, so you can't just say "whatever you want to call it".

 

I'm guessing you may not have seen in my post, but I purposely included three separate external links with the relevant source data specifically for the reason you mention. I'll repost them here for anyone who wants to read them, but they're in my original post as well. It was just easier to direct OP to my existing post where I had already compiled the relevant external links vs. copying and pasting them again here.

In this article, the very first sentence says that torque is always equal at each wheel. It then goes on to explain in more detail how it works.
https://auto.howstuffworks.com/differential3.htm

In this article, their exact quote is:
"The practical application of this is that open differentials, the cheapest and most common type, always split the force from the Trg half to one wheel and half to the other…50/50. Yes, always. I’ve heard that with an open diff all the power goes to the wheel with the least traction, the path of least resistance, and all that. I hear you say. To which I would say in my best Adam Savage: Myth Busted!"
https://oppositelock.kinja.com/your-...rks-1661277563

And in this video, it's also explained around the 1 minute mark.

 

^^^^^ This. It's most likely traction control sending brake pressure pulses to the wheel attempting to spin. If wheel traction is dead even they'll both spin without any inputs from traction control, but that's a fairly rare situation. If it's TC doing it's thing, you'll feel a little herky-jerky from the rear of the truck as the brake is pulsed.
FWIW, I wish Ford would offer a Torsen or a True-track instead of the ELD, which must be un-powered to be engaged if wheel spin is occurring. I put one in my last 150 and its like the best of both worlds, between a limited slip and an ELD. -- Frankly with regard to 95% of the trucks being driven daily, the ELD is a sales gimmick. An old school LS is more practical and useful. The only problem is they require periodic maintenance and occasional service (re-clutching) so in today's world they're probably doomed.