Brake Lock Differential vs Dana TrueTrac Limited Slip Differential

[Smittie]

I have a 2021 Jeep Gladiator, Dana M210 front axle. The rear axle already has a limited slip differential. The front diff is currently open. The Gladiator does have Jeep's Brake Lock Differential system which I have seen/felt work.

Does the Dana TrueTrac Limited Slip Differential provide significant improved traction over the Brake Lock Differential system?

Article on Jeep's Brake Lock Differential for reference:

https://blog.stellantisnorthamerica.com/2008/02/11/jeep-brake-traction-control-explained/

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[GuzziMoto]

I have a 2021 Jeep Gladiator, Dana M210 front axle. The rear axle already has a limited slip differential. The front diff is currently open. The Gladiator does have Jeep's Brake Lock Differential system which I have seen/felt work.

Does the Dana TrueTrac Limited Slip Differential provide significant improved traction over the Brake Lock Differential system?

Article on Jeep's Brake Lock Differential for reference:

https://blog.stellantisnorthamerica.com/2008/02/11/jeep-brake-traction-control-explained/

My experience. We started with a 2016 JKU Wrangler (not a Gladiator, but the story is relevant). It came with the factory clutch based limited slip and had the Jeep Brake Lock Differential. The factory clutch style limited slip is weak. It is more of a "limited slip suggestion". And as the unit wears, it gets weaker. We replaced that with a TruTrac limited slip at about 30,000 miles. Not added it to the front but replaced the factory limited slip in the rear with it. The difference was pretty big, it had noticeably more traction, and we found we could wait until trails got harder before we had to shift into 4WD.
In fact, the factory Brake Lock Differential seemed to work in combination with the TruTrac, as instead of the driver having to apply the brakes when a wheel is in the air and spinning the Brake Lock Differential does it for you automatically.
We also installed a locker on the front, But I could count on my fingers how many times we have engaged that locker. 98% of the time the TruTrac in the back is all we have needed.
I rate it as some of the better money spent on our Wrangler, and I have spent a fair amount on it.
I plan on adding one to our JT, in the rear.
It sounds like you are talking about adding it to the front. While you can do that, personally I would rather have a locker up front, one you can lock when you want and leave open when you don't. I am also not sure about having a stronger traction device up front than you have in the back, the mechanical limited slip is, in my experience, substantially stronger than the factory limited slip in the rear. The factory limited slip also has a reputation for eating spider gears. So that was another reason why I replaced ours with the TruTrac, and plan on doing the same/similar with our recently acquired JT. It also has the clutch style factory limited slip. That will be going away.

 

[Gvsukids]

Dana TrueTrac Limited Slip Differential

https://www.jeepgladiatorforum.com/...-limited-slip-differential.16636/post-1141156

 

[Badunit]

"Brake Lock Differential" is nothing like a locker or limited slip. It is a poor man's substitute and hurts as much as it helps. If you slip too much or the good traction is moving from wheel to wheel, it brakes you (and cuts engine power) until you are at a standstill. It can't handle those conditions, which are typical snow and ice. It seems to be okay at getting you started in a bad traction condition but not so good at keep you moving. I've been able to go further with it off than on. When I see BLD in operation I wonder how it isn't breaking axles with all that jerky braking with power applied.

I can't speak to the effectiveness of the stock limited slip. I don't have it.

Are you allowed to put limited slip in the front? It might affect steering.

 

[Smittie]

@GuzziMoto, thank you. I didn't realize that the limited slip was other than a Dana unit. I will probably take your suggestion.

 

[GuzziMoto]

@GuzziMoto, thank you. I didn't realize that the limited slip was other than a Dana unit. I will probably take your suggestion.

There are other brands that make essentially the same thing, a mechanical limited slip used a Torsen gear setup. The Eaton TruTrac (TrueTrac) is just a name brand. Other companies also seel them. But they are distinctly different from the variety of clutch based limited slips, which is what the factory limited slip is. All a clutch based limited slip does is use clutch plates that provide a certain amount of friction that tries to make the two sides spin at the same speed, but as the two sides need to spin at different speeds when, say, going around a corner, there has to be enough slip to allow them to travel at different speeds when required. That slip tends to wear the clutch plates. As the clutch plates wear they offer less friction, so they provide less limited slip functionality. Plus that clutch plate wear is being carried by the oil in the diff. Some people think that is why the factory limited slips tend to eat their spider gears. It makes sense to me. But I would not call that a fact. They do seem to eat their spider gears, though, whatever the reason. Changing the diff oil often seems to help prevent that. Seems to.
The mechanical limited slip using the Torsen gearset allows some difference in speed between the two sides, but when that difference becomes too much it send power to the slower side. That point seems to vary, depending on how much torque you are sending through it. For example, making a turn on pavement at light throttle may not do anything, but if you apply enough throttle the natural difference in speed between the two sides combined with the higher torque application will cause the Torsen gearset to try to spin the inside tire to make it spin to match the outside tire, which is spinning faster because it is traveling farther. The clutch style stock limited slip does not do any of that. It is just a set amount of suggestion that the two sides spin the same speed, and that amount of suggestion decreases as the clutches wear.
Replacing the stock limited slip in the rear with the Eaton TruTrac was money well spent in my opinion. I know a number of people who also have a TruTrac in the front axle, and that works fine there. But if you apply enough throttle on grippy surfaces the TruTrac in teh front can be felt as it tries to make the two front wheels spin the same speed. That is why I prefer a selectable locker there. But there is no wrong answer, just different options with different advantages. Some prefer the TruTrac to a locker because you don't have to remember to turn it on. And for many a TruTrac is all they will ever need. But, for those that spend time with one or more wheels in the air a locker can be the better choice. I view the TruTrac in back and a locker up front to be my ideal compromise.

 

[BlueScapegoat]

I hate brake based LSDs, I don't think they should even be allowed to call them limited slip (although Jeep might not specifically call it it, it's become colloquial to do so in the industry.) It's just traction control and it's functioning the same way traction control does. I hated it in my Raptor, I hate it in my Gladiator. I usually refer to them as subtractive traction devices, since they take power away by braking the spinning tire to cause the other to spin. They feel bad and they're unpredictable. But, to be fair, they do work much better than an open diff for obvious reasons. Before any of this tech came about, one of the wheeling tricks when you were stuck with one tire spinning and open diffs was to apply brake pressure yourself and it'd help push some power to the other tire. It's just doing that for you. The BLD doesn't do anything in the differential.

Clutch based LSDs are ok. I don't like anything that wears and gets overly hot in my diff and needs an eventual rebuild.

Proper helical gear LSDs are awesome.

People say you can't have both a true LSD and a locker in the same differential... but the TJ Rubicon did. Both a helical LSD and selectable locker. Auburn made one called the ECTED as well although I think that one was a clutch pack.

 

[NC_Overland]

My experience. We started with a 2016 JKU Wrangler (not a Gladiator, but the story is relevant). It came with the factory clutch based limited slip and had the Jeep Brake Lock Differential. The factory clutch style limited slip is weak. It is more of a "limited slip suggestion". And as the unit wears, it gets weaker. We replaced that with a TruTrac limited slip at about 30,000 miles. Not added it to the front but replaced the factory limited slip in the rear with it. The difference was pretty big, it had noticeably more traction, and we found we could wait until trails got harder before we had to shift into 4WD.
In fact, the factory Brake Lock Differential seemed to work in combination with the TruTrac, as instead of the driver having to apply the brakes when a wheel is in the air and spinning the Brake Lock Differential does it for you automatically.
We also installed a locker on the front, But I could count on my fingers how many times we have engaged that locker. 98% of the time the TruTrac in the back is all we have needed.
I rate it as some of the better money spent on our Wrangler, and I have spent a fair amount on it.
I plan on adding one to our JT, in the rear.
It sounds like you are talking about adding it to the front. While you can do that, personally I would rather have a locker up front, one you can lock when you want and leave open when you don't. I am also not sure about having a stronger traction device up front than you have in the back, the mechanical limited slip is, in my experience, substantially stronger than the factory limited slip in the rear. The factory limited slip also has a reputation for eating spider gears. So that was another reason why I replaced ours with the TruTrac, and plan on doing the same/similar with our recently acquired JT. It also has the clutch style factory limited slip. That will be going away.

I’d say it’s semi relevant. I think they’ve improved it bs older models because mine never worked very well on older Jeeps. My JT track lock works surprisingly well. I don’t have 37s, I have 34s, but it works great. I change the fluid every 60k miles though.

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