Which limited slip is best?

[sgtsandman]

Locking differential from Dodge: https://parkingzonepost.files.wordpress.com/2011/02/pblock.jpg

Used properly, that can be a traction assisting device. Some sheet metal may be damaged in the process.

 

[rubydist]

@gw33gp - your statements are getting more and more incorrect. A locked differential does NOT send 50% of the torque available to each axle all the time! A locked differential sends the same rpm to each wheel regardless of the torque, including cases where 100% of the torque goes to one wheel and 0% goes to the other.

What you are not understanding is my statement of "effectively locked" If you have a bolt that is torqued so that it takes 100 lb-ft to loosen it, if you only have 50 lb-ft available to attempt to loosen it, it is "effectively locked". Same thing with a differential - if the diff requires 500 lb-ft of torque bias to allow it to differential, and the tire can only provide 300 lb-ft of torque, the differential is "effectively locked."

If you have a Torsen diff axle with one wheel in the air, only that wheel will spin no matter how fast you spin it, because the Torsen diff will not "lock" when there is no torque on it. The only way to get the vehicle to move forward in your example above is to put your foot on the brake, so that there is some torque required to turn the wheel that is in the air. btdt.

 

[sgtsandman]

Ronny Dahl did a video or two on this a few years back to illustrate what is being said here.

In the end, an LSD is better than an open differential and a locked differential is better than an LSD.

Now, bear in mind that this is from an off road driver’s point of view.

On road, especially on a slippery surface, a locked differential can be down right detrimental, as mentioned by 85. I’ve experienced the same thing.

Driven correctly, and LSD can be better but that can also be said by an experienced driver that has open differentials.

We can beat this horse until it’s a bloody pulp and it won’t change the opinion of some people on the subject.

Lets get back to addressing the OP’s question and just leave it at that before it gets ugly and I see it going that way. Ok?

 

[00t444e]

A locked differential does not have a torque bias. It sends 50% of the torque available to each axle all the time. An LSD sends a percentage of the torque of the axle with the least traction to the axle with the most traction. The T-1 Torsen can approach sending 100% of the torque of the axle with the least traction to the axle with the most traction but the T-2 Torsen (what comes in the Ranger) cannot get near that. The T-2 Torsen just has a higher torque bias than a stock clutch type LSD. You put one of your rear wheels in the air and put the transmission in gear at idle and let out slowly on the clutch, that tire in the air will just spin with a T-2 Torsen. A locked deferential would drive both wheels equally and your vehicle would move forward. If you accelerate (increase engine rpm) while doing this with a T-2 Torsen, you should move forward slowly because you are increasing the torque to the axle with the least traction and the stalled axle will get a percentage of that.

I also agree that a stock clutch type LSD is better suited for street driving.

That's not entirely true, a locker makes both wheels spin at the same speed, torque to each wheel will vary depending on the amount of traction each wheel has. With a locker if one wheel is in the air and one is on the ground almost 100% of the torque will be going to the wheel that is on the ground. This video explains it well.

 

[00t444e]

On road, especially on a slippery surface, a locked differential can be down right detrimental, as mentioned by 85. I’ve experienced the same thing.

An auto locker in the rear axle is no more detrimental on a slick surface than a factory clutch type limited slip is, in fact it is somewhat less because in turns an auto locker will unlock and allow the outside wheel to freely overrun the inside wheel whereas with a clutch type limited slip there is always pressure on the clutches trying to keep both wheels spinning at the same speed. Also a clutch type limited slip will fail you when you need it the most like when going up a hill with one tire on ice and one on a higher traction surface, an auto locker will keep both wheels spinning at the same speed.

 

[sgtsandman]

An auto locker in the rear axle is no more detrimental on a slick surface than a factory clutch type limited slip is, in fact it is somewhat less because in turns an auto locker will unlock and allow the outside wheel to freely overrun the inside wheel whereas with a clutch type limited slip there is always pressure on the clutches trying to keep both wheels spinning at the same speed. Also a clutch type limited slip will fail you when you need it the most like when going up a hill with one tire on ice and one on a higher traction surface, an auto locker will keep both wheels spinning at the same speed.

The locker I'm talking about is a select able locker such as a e-locker, air locker, or mechanical locker, not an auto locker.

 

[00t444e]

The locker I'm talking about is a select able locker such as a e-locker, air locker, or mechanical locker, not an auto locker.

A mechanical locker is an auto locker, but yes a locked selectable locker is the same as a spool, that's why I don't use selectable lockers in a rear axle because they are worthless for street driving.

 

[sgtsandman]

A mechanical locker is an auto locker, but yes a locked selectable locker is the same as a spool, that's why I don't use selectable lockers in a rear axle because they are worthless for street driving.

The Ox locker is mechanically selected to be locked or unlocked via a cable and a lever and the one I had in mind. They also offer a couple other options, air and electronic - I think. I can see where one would be confused since auto lockers are also called mechanical lockers. They operate mechanically, so it isn't a misnomer. How they operate is different.

Ford 8.8 OX Locking Differential (2.73+) (28 Spline Ct.) - OX Offroad

OX Lockers can instantly lock differentials and allow you to tackle the toughest off-road terrain. The world's best traction aid, OX Lockers keep you moving in all conditions. OX Lockers are available in 3 different shifting methods Manual, Air, or Electric shift, and are offered in over 30...

ox-usa.com

 

[Lefty]

Actually I do understand the math (I am a mechanical engineer), which is why I posted what I posted: "the torque bias that it takes to make it differential under load is so high that it is effectively locked" If the torque bias required for the mechanism to differential is higher than what is able to be provided by the tire friction, then it is effectively locked.

We don't need to clutter this thread with this - I just posted my personal experience and why that is the case. You don't have to agree with me.

I found this interesting.

 

[Lefty]

The new spare same size is a good idea - you just need to include in your tire rotation - otherwise a new spare is significantly larger than a worn out tire. I always put the spare on the front, and the front on the rear when I have a flat for that reason - 50 miles on a 235/75R15 when rest of the tires are 31x10.5R15 would be really hard on "clutch" differential.

Exactly. Thanks!

 

[Lefty]

The Ox locker is mechanically selected to be locked or unlocked via a cable and a lever and the one I had in mind. They also offer a couple other options, air and electronic - I think. I can see where one would be confused since auto lockers are also called mechanical lockers. They operate mechanically, so it isn't a misnomer. How they operate is different.

Ford 8.8 OX Locking Differential (2.73+) (28 Spline Ct.) - OX Offroad

OX Lockers can instantly lock differentials and allow you to tackle the toughest off-road terrain. The world's best traction aid, OX Lockers keep you moving in all conditions. OX Lockers are available in 3 different shifting methods Manual, Air, or Electric shift, and are offered in over 30...

ox-usa.com

Very interesting...not for me, but this seems to be a nice option.

 

[sgtsandman]

Very interesting...not for me, but this seems to be a nice option.

There is two big things to me that are a negative with the mechanical OX locker. 1) there is no drain plug. 2) You have to cut a hole in the floor after you find a good spot to put the actuating lever. Not a lot of good options in a manual transmission late model Ranger with the way the cup holder trim piece is made and placed. As in none unless you rip out the trim piece with the cup holders and throw it in the trash.

Certainly not an option for you and what you are looking for. The thread just took a hard turn away from what you were asking about.

 

[Lefty]

A friend of mine has a locker on his Mustang Cobra. It makes sense for his purposes, but I'm still looking for a limited slip. Trac Lock seems to be my first choice. I would imagine it's a little more well mannered. Torsen is second. Your comments were certainly helpful.

 

[Lefty]

There is two big things to me that are a negative with the mechanical OX locker. 1) there is no drain plug. 2) You have to cut a hole in the floor after you find a good spot to put the actuating lever. Not a lot of good options in a manual transmission late model Ranger with the way the cup holder trim piece is made and placed. As in none unless you rip out the trim piece with the cup holders and throw it in the trash.

Certainly not an option for you and what you are looking for. The thread just took a hard turn away from what you were asking about.

Yes, but I don't mind. People like to weigh in. I didn't know there were so many different options for the Ranger.

 

[lil_Blue_Ford]

I have had a rear auto locker in 4 vehicles, drive in the snow every winter and never had any issues with it not turning in 2wd.

Congrats, do you want a cookie? My experience has been a tendency to push the truck in a straight line with a locker. Or at least the cheap Lock-Right that’s in my F-150. Maybe a better locker would act differently. Maybe different weather conditions or road conditions affect it. I can only really speak from my experience.