[k7cej]

I ordered my LR LWB XLT 350 Wagon with a 3.31 limited slip differential (LSD). I have never owned or operated a vehicle with a LSD. While I am waiting for delivery (next week, hopefully!) I have two questions:
1. Are there driving tips or precautions I should be aware of with the LSD?
2. Does anyone know of the exact type of technology employed by this differential?

 

[PeterR]

http://www.fordtransitusaforum.com/...mited-slip-differential-benefit-downside.html

http://www.fordtransitusaforum.com/ford-transit-general-discussion/1385-rear-axle.html
.
.

 

[Damien89]

Just watch out in the corners in the wet/ice as the backend can slide out if you give it too much gas because both/all rear wheels slip in slippery conditions.

 

[hammerdown]

I've ordered the LSD as well. 3.73 Diesel for me. I think that with the traction control and stability program you don't really have to worry about getting sideways in the corners. If you wanted to call the potential to get squirrelly a drawback of the LSD (and I wouldn't) the stability program would negate this concern. I have two cars with LSD rears. One is a 78 Firebird Formula 400 and it will bite you hard making a left on dry pavement under hard throttle. The other is my G8 GT, independent rear suspension, and tons of power, but it has a very intuitive stability program. If I get a little spicy with the go pedal it does an almost seamless job of making me look like a race car driver. Turn off the ESP and it's a whole different animal. IMO no drawback or real concerns about having the LSD in the Transit. You'll love it in the snow. My G8 with skinny snow tires is spectacular in the snow.

I believe it's a clutch type LSD in the Transit. Can anyone confirm?

 

[PeterR]

The earlier threads (links posted on Wednesday in post #2 ) have quite a bit of useful information in them FYI.

 

[VanMan]

I've ordered the LSD as well. 3.73 Diesel for me. I think that with the traction control and stability program you don't really have to worry about getting sideways in the corners. If you wanted to call the potential to get squirrelly a drawback of the LSD (and I wouldn't) the stability program would negate this concern. I have two cars with LSD rears. One is a 78 Firebird Formula 400 and it will bite you hard making a left on dry pavement under hard throttle. The other is my G8 GT, independent rear suspension, and tons of power, but it has a very intuitive stability program. If I get a little spicy with the go pedal it does an almost seamless job of making me look like a race car driver. Turn off the ESP and it's a whole different animal. IMO no drawback or real concerns about having the LSD in the Transit. You'll love it in the snow. My G8 with skinny snow tires is spectacular in the snow.

I believe it's a clutch type LSD in the Transit. Can anyone confirm?

So when did they start putting Traction control in the Transit?
I have seen one Mid roof/LWB that has been rolled already......

 

[PeterR]

So when did they start putting Traction control in the Transit?
I have seen one Mid roof/LWB that has been rolled already......

The earlier thread discussed it, for instance post #38 here:

http://www.fordtransitusaforum.com/...-differential-benefit-downside.html#post81641

http://www.fordtransitusaforum.com/...mited-slip-differential-benefit-downside.html

Owners manual re TCS:

http://www.manualslib.com/manual/745073/Ford-Transit-2015.html?page=142#manual

 

[VanMan]

The earlier thread discussed it, for instance post #38 here:

http://www.fordtransitusaforum.com/...-differential-benefit-downside.html#post81641

http://www.fordtransitusaforum.com/...mited-slip-differential-benefit-downside.html

Owners manual re TCS:

Using Traction Control; Principle Of Operation; Stability Control - Ford TRANSIT 2015 Owner's Manual [Page 142]

I DONT TAKE DIRECTION FROM YOU,
I can see you are back to the forum A-HOLE telling everyone what to do
Must be the new members who don't know you have made a fool of yourself many times before

 

[PeterR]

. . . , just showing a path to interesting further discussions . . . For those who wish to learn from others . . .

 

[Longboard]

Driving through Kentucky last Sunday in slick ice and snow I was trying to decide whether to turn TC off and let LS do it's job or not.
I was cruising up the Interstate at about 65 mph.
Should I have left it on or off under those circumstances?

 

[USMC Vet]

I DONT TAKE DIRECTION FROM YOU,
I can see you are back to the forum A-HOLE telling everyone what to do
Must be the new members who don't know you have made a fool of yourself many times before

VanMan,

I take it you are having a bad day. Just read the entire threads referred to by PeterR. He wasn't telling anyone what to do, he was providing links for others having the same questions about something he hadn't used before and also had questions about, when they asked the same questions or provided the answers. Basically, your post was uncalled for and immature.

Semper Fi

 

[skagitstan]

I DONT TAKE DIRECTION FROM YOU,
I can see you are back to the forum A-HOLE telling everyone what to do
Must be the new members who don't know you have made a fool of yourself many times before

Uh-oh, internet tough guy syndrome strikes someone, somewhere, every 2.73 seconds.:|

Even as one of those dread newbies here, I can still manage to appreciate the usefulness of TC as well as LS (not to mention LSD). I also know that any turkey can roll any vehicle if they try hard enough...(perhaps especially if equipped with LSD>). It's just easier without the TC or SC.

I will have LS on my impatiently awaited van, but only expect to use it when I'm going slow for good reason, especially on unpaved steep back quasi-roads, where losing power based on a computer algorithm is contra-indicated. In other words, the sort of times TC won't cut it.

 

[orton]

I thought LS was a mechanical design that is operational all the time. The TC traction control can be turned on/off but LS is always there.

Can someone explain when the TC should be tuned off when you have a LS rear end? Do not understand how they function together.

 

[Epps]

skagitstan nailed it! "only expect to use it when I'm going slow for good reason, especially on unpaved steep back quasi-roads, where losing power based on a computer algorithm is contra-indicated. In other words, the sort of times TC won't cut it.". LS is mechanical, a set of disks that interlock within the rear differential to allow power to both rear axles more so at low speeds. TC uses the brakes to maintain control/power to all four wheels. TC will not help at low speeds.


Epps

 

[Longboard]

So on or off for my icy Interstate 65mph drive?

 

[orton]

skagitstan nailed it! "only expect to use it when I'm going slow for good reason, especially on unpaved steep back quasi-roads, where losing power based on a computer algorithm is contra-indicated. In other words, the sort of times TC won't cut it.". LS is mechanical, a set of disks that interlock within the rear differential to allow power to both rear axles more so at low speeds. TC uses the brakes to maintain control/power to all four wheels. TC will not help at low speeds.
Epps

So turn TC off at low speeds in low traction situations with LS? At what speed would you turn it back on?

 

[PeterR]

turnoffthelights had this to say about the interplay of TCS and LS on that other thread. I don't pretend to understand it, but there are a lot of other nuances discussed there which I hope to be messing around with soon on my new Wagon. Best guess is that TCS works best at higher speeds, but that there will be times, perhaps at lower speeds, and maybe in reverse, when it is best to turn off the traction control and let the limited slip differential do its job on its own.

TBD for sure.

PS Edit -- skagitstan's comment is consistent with this I think. Again -- need to test in real time. Limited slip is on full time, however, and cannot be turned off.

This is such a fun subject.
To aid in understanding TC (traction control) vs LSD (limited slip differential). Some Ford Lightning owners complain of smoking only one tire off the line after 60,000 miles. This occurs when the limited slip has passed is't useful life. It can no longer split traction to both drive wheels as designed. The Lightning uses identical LSD technology. When the clutches wear out the differential is now 'open'.

TC for the Transit is not a torque vectoring or racing type of system. It just tries to keep the vehicle wheels spinning at the same RPM. It does this by decreasing engine output as well as applying brakes to match the opposing wheel's RPM. TC does not care what hill you attempting to climb or how slippery your driving surface is. TC is a safety feature, that's it.

TC shoots LSD's in the foot. LSD's require a loss of traction to work. When the wheel with less traction begins to spin, the clutches clamp down. The clutches transfer power to the non slipping wheel; therefore limiting the slip. That is it.

When decelerating, an LSD can also keep the vehicle straight in a hard braking situation or on decelerating on slippery stuff. If one drive wheel begins to lock up, the clutch pack clamps down and makes the non-spinning wheel spin. As far as I have read, TC does not intervene unless the power is being applied. The job of ABS is for deceleration and can never be turned off; whereas TC can. ABS can't make a wheel turn and neither can TC. Only LSD or similar can perform this safety function.

 

[alarmist]

So turn TC off at low speeds in low traction situations with LS? At what speed would you turn it back on?

The F150 guys have probably sorted all this out. Might try one of those forums for specifics of the Ford electronics/LSD interaction.

 

[Airedrifter]

So on or off for my icy Interstate 65mph drive?

On. It will help in emergency braking situations. LS is still active and will help too.

IMHO, you really only ought to turn off TC when you are specifically trying to get enough traction to escape a low speed spinning situation. As soon as you're out of the situation, turn on TC to help in panic brake situations or skids.

 

[hammerdown]

The F150 guys have probably sorted all this out. Might try one of those forums for specifics of the Ford electronics/LSD interaction.

Most F-150 guys in my neck of the woods are too busy texting and driving like d-bags to pay attention to the actual road >

Re Longboards concern about on or off at highway speeds. It should be on at all times except low speed low/no traction situations, which is where the LSD is your friend. Like already mentioned above. But Longboard and I come from Sprinters, where even when the ESP is switched off, at low speeds, when you break 60km/h it automatically turns back on.

ESP won't keep it shiny side up if you get into trouble or perhaps leave the road unexpectedly.