No Limited Slip Differential : What's the impact on Towing?

[Boostedbus]

is that a 70 cougar I spy? Drag pak eliminator?

That’s my 69 Eliminator with the 390 4V IP engine. No drag pack option but it does sport factory air conditioning. If the person ordering it checked the A/C option then it came with 3:00 ratio axle and automatic with no other gear/ trans options. The 428 cars got 3:25 ratio only with air and automatic. The irony is that a automatic with air car is worth more than a 4sp car because of no A/C option, but a drag pack car 3:91 ratio or super drag pack with 4:30 will bring premium money. I have two different 9” third members set up that I switch back and forth with, one is a 3:50 Detroit locker, and the other is a 4:11 Full Spool which currently in the car now. I got rid of the 3:00 open dif. right after putting it on the road after I restored it. I could smoke the right rear for eternity before it hooked up. The car had to try and catch the tire! Lol! Sorry for the high jack!

 

[JExpedition07]

Yes once you have a vin it’s generally too late. I really wouldn’t sweat it too much especially in an Expedition or any Suburban class vehicle. It’s a nice option but not a killer. I’ve been driving in Buffalo NY since I began, these things are pretty much tanks in the snow. You also get 4H in the new ones again, which helps all with braking in nasty icey roads as brake torque is split between front and rear so less ABS and skidding. In a sense they got better this year. Have fun with it.

 

[mlogan]

I don't have it in my '15 and I can see (at least with my driving style) that it would come in handy so checked that box on the '22 I ordered. Particularly turning starts or slick MN roads. Leaving in 4A all winter so far based on someone's suggestion here has been helpful and limits most of those torque/power cutting issues when the computer senses slipping.

 

[Boostedbus]

The only drawback on having a LSD vs. an Open differential is possibly a very slight difference in fuel mileage being worse for the LSD. With the LSD you have a resistance when turning to make the clutches slip which will scrub the roll which in turn scrubs fuel economy. I would have to guess it’s very minimal though. For me I’ll take the added traction over the economy all day long….. especially since it’s a minimal difference.

 

[LokiWolf]

The only drawback on having a LSD vs. an Open differential is possibly a very slight difference in fuel mileage being worse for the LSD. With the LSD you have a resistance when turning to make the clutches slip which will scrub the roll which in turn scrubs fuel economy. I would have to guess it’s very minimal though. For me I’ll take the added traction over the economy all day long….. especially since it’s a minimal difference.

Nope, you are using Old-School knowledge to make this determination. The Expedition since 2018+ has had an ELSD. The clutches are electronically controlled, so no slipping clutches, because they aren't engaged. They are only engaged when wheel slip occurs, and steering angle is factored in to that decision. These are an open diff, until the ELSD decides to get involved. What you said would be 100% accurate with a mechanical LSD.

The ELSD in the Expedition is the best of both worlds, not engaged when not needed, and there when you do.

Also, there are several Pre 4th gen owners in this discussion...If your Expedition is equipped with an LSD, it is mechanical, and not the same. I have learned you have to REALLY pay attention to realize when the ELSD is getting involved in these 4th gens. It works REALLY well! If you don't think it is working turn off TC, and floor it in Wet conditions, and you will notice a difference.

Also, the ELSD was compared to the brake based TC. No where near the same. Yes, brake based traction control has gotten WAY better over the years, but still not a replacement for a good LSD, manual or Electronic. Brake based TC, stops one wheel from spinning to "Push" power to the one that has traction. Quickly modulated using modern ABS tech it works pretty good, but a LSD moves the power without slowing one wheel.

 

[balthisar]

Also, there are several Pre 4th gen owners in this discussion...If your Expedition is equipped with an LSD, it is mechanical, and not the same.

This comment made me realize I'm an idiot so I went out and looked at the axle code for my '04, telling my I have LSD and 3.73. While I recognize that it's mechanical and not electronic, I like this truck in the winter, and have fun flooring it on the icy neighborhood roads (when it's safe). It suddenly occurred to me that I never feel the ABS/TC going crazy like on other cars, and I really like that.

My build date was pushed back to the week of Feb-21 for some reason, so I wrote to my salesman this morning asking him to add 62E to my order. The axle isn't encoded into the VIN, so hopefully he can make this change without affecting timing.

 

[duneslider]

So, curious on this, I am going to have to do some testing if the snow comes back but I have been pretty certain in 4a with the knob turned to the snow,mud,whatever option I still get the nanny shutting me down when wheel spin is happening? I have been pushing the TC button to allow for wheel spin as that works better for me. But what you are saying is that the eLSD is disabled if I push the TC button? That sort of doesn't make sense? If that is true, what option in the drive settings will allow me to spin the tires in the snow and not cut the power?

I live up a hill and when the snow is deep even in 4a some wheel spin is needed. I had assumed that the snow mud setting would allow wheel spin but my experience is that it doesn't and power is still cut.

 

[LokiWolf]

So, curious on this, I am going to have to do some testing if the snow comes back but I have been pretty certain in 4a with the knob turned to the snow,mud,whatever option I still get the nanny shutting me down when wheel spin is happening? I have been pushing the TC button to allow for wheel spin as that works better for me. But what you are saying is that the eLSD is disabled if I push the TC button? That sort of doesn't make sense? If that is true, what option in the drive settings will allow me to spin the tires in the snow and not cut the power?

I live up a hill and when the snow is deep even in 4a some wheel spin is needed. I had assumed that the snow mud setting would allow wheel spin but my experience is that it doesn't and power is still cut.

Snow/Mudd does allow more wheel speed, but not as much as turning TC off(Momentary press). There is contradicting info on the ELSD being shut down when TC is off. One of the 4WD supplements alludes all electronic traction aids are minimized/off when TC is off. The current print of my 2020 Manual from Fords site implies ELSD is on all the time. I feel it isn't. Guess like you I need to play more.

In your circumstances, I would try Mudd, with TC off, and ELSD in locked mode. That will allow wheel spin.

 

[Anerbe]

I have learned you have to REALLY pay attention to realize when the ELSD is getting involved in these 4th gens. It works REALLY well! If you don't think it is working turn off TC, and floor it in Wet conditions, and you will notice a difference.

I agree with this - I have to put my Gen 4 in conditions to test out the ELSD - I've never needed to manually activate it to help a situation.

Great test is turning TC fully off, and putting the car in 2WD with one side of the car over ice on an incline. When turning off TC completely, but activating locking diff, there's no slip, as i've tested multiple times. Zero slip and no cut of power.

I need to test with no TC, and not activating rear lock, what the car does - either it will spin the ice end of the real axle, or it will automatically redistribute to the traction side and allow me to go up.

May do it after work today ;-)

 

[Boostedbus]

Nope, you are using Old-School knowledge to make this determination. The Expedition since 2018+ has had an ELSD. The clutches are electronically controlled, so no slipping clutches, because they aren't engaged. They are only engaged when wheel slip occurs, and steering angle is factored in to that decision. These are an open diff, until the ELSD decides to get involved. What you said would be 100% accurate with a mechanical LSD.

The ELSD in the Expedition is the best of both worlds, not engaged when not needed, and there when you do.

Also, there are several Pre 4th gen owners in this discussion...If your Expedition is equipped with an LSD, it is mechanical, and not the same. I have learned you have to REALLY pay attention to realize when the ELSD is getting involved in these 4th gens. It works REALLY well! If you don't think it is working turn off TC, and floor it in Wet conditions, and you will notice a difference.

Also, the ELSD was compared to the brake based TC. No where near the same. Yes, brake based traction control has gotten WAY better over the years, but still not a replacement for a good LSD, manual or Electronic. Brake based TC, stops one wheel from spinning to "Push" power to the one that has traction. Quickly modulated using modern ABS tech it works pretty good, but a LSD moves the power without slowing one wheel.

Yes my 17 EL has 3.73 LSD which is what I was referring to. Thanks for clarifying how the ELSD works. It makes sense that it works/kicks in, only when needed now. I guess my thoughts on this new electronic system is that it takes more systems like wheel speed sensors needed to support it making it more complicated and possibly less reliable. With that being said it’s definitely has to have a better drivability experience than say a full spool which I’d consider the most reliable positive traction set up made. The draw back with a spool is it never unlocks unless it broke and not unlocking in a turn makes for a ton of push on the front steering wheels and wheel hop on the rear which makes for an interesting driving experience…….. steering with the rear wheels….drifting!