Brake Lock Differential (BLD) techniques for open diff (non-locker & non-LSD) JLs

[Htfan]

Looking to hear from those who have experience with the JLs (and JKs) Brake Lock Differential (BLD) feature to "semi-lock" both wheels on an axle (by simultaneously applying the brake/throttle) in "real trail" situations. I realize it's much easier to lock your diffs or rely on a Limited Slip diff if your JL is equipped (Rubicon etc).

However, from many articles I've read I'm realizing the open diff JLs (Sport/Sahara etc) are also very capable without lockers. It seems to take more technique to utilize the BLD functionality since it's not as simple as pressing the locker button.

How do you utilize BLD on difficult trails or snow/mud etc? Do you:

1) Two foot drive (left on brake/right on throttle)
2) Use handbrake to "lock" rear axle only
3) something other

Note: ESC is turned off when offroad

I have a Sport with open diffs (M186/M200) and have been researching axle upgrades (Lockers/LSD etc) until I ran across the BLD function of our open diff JLs.


Appreciate your input!

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[jludave]

How do you utilize BLD on difficult trails or snow/mud etc? Do you:

1) Two foot drive (left on brake/right on throttle)
2) Use handbrake to "lock" rear axle only
3) something other

3 - Drive normally and let the vehicle do what it needs to do. There is nothing special nor any driving technique you need to perform for BLD to work. It kicks in as needed.

 

[BrokenDana35]

^what JLUDave said. Drive normally and the computer will detect any wheel speed sensor differences and take care of the rest.

In high traction environments such as Moab it’s as good as a locker!

 

[Htfan]

3 - Drive normally and let the vehicle do what it needs to do. There is nothing special nor any driving technique you need to perform for BLD to work. It kicks in as needed.

Appreciate your input. This makes sense for crawling.

However, "drive normally" would not apply to "slippery" trails with snow/mud. I don't normally ride the brake pedal on a dry trail.

There needs to be an "intentional" brake application to engage BLD.

 

[Htfan]

^what JLUDave said. Drive normally and the computer will detect any wheel speed sensor differences and take care of the rest.

In high traction environments such as Moab it’s as good as a locker!

In some of my own experiences, this is not the case. It seems there needs to be some intentional brake application before the non-traction wheel will engage. Otherwise, it just spins like an open diff does.

 

[jludave]

There needs to be an "intentional" brake application to engage BLD.

Nope. The vehicle does what it needs to do. I don't manipulate the brake pedal any differently in slippery/snowy conditions.

 

[AcesandEights]

The vehicle senses wheel slipping and applies brakes to transfer power. If you apply brakes it's to both sides, negating wheel slippage, making the vehicle think there isn't a need to apply it to the one slipping. The driver should apply throttle not brake.

ETA: BLD tries to get the tires to turn at the same speed. If you apply the brakes, you limit that, and the torque. That results in you overriding BLD, and torque not being transferred. Here is an explanation: https://blog.stellantisnorthamerica... apply brake pressure,the wheel on the ground.

Key points:
Using the vehicle’s wheel speed sensors, BLD knows when one wheel on a driven axle is turning and the other is not. BLD will apply brake pressure to the wheel that is turning. (emphasis added)

In order to get the most out of BLD, the driver must adapt their driving style to characteristics of BLD. For example, when in a situation where one or more wheels loose traction and the vehicle will not continue in the desired direction, the driver should carefully and smoothly apply the throttle to allow more torque to go the wheels with traction as the brake(s) are applied. (emphasis added)

BLD looks at individual driven axles and tries to keep the wheels turning at the same speed.

 

[aldo98229]

You may be thinking of the situation when you have an LSD and one of the wheels ends up in the air.

In that situation, the LSD will fail to activate, so you apply the brake gently to trick the system into engaging.

 

[aldo98229]

Here’s a somewhat related thread: https://www.jlwranglerforums.com/fo...action-control-brake-lock-differential.55438/

 

[Htfan]

You may be thinking of the situation when you have an LSD and one of the wheels ends up in the air.

In that situation, the LSD will fail to activate, so you apply the brake gently to trick the system into engaging.

Yes, this is also my experience.

However, I don't have an LSD and my open diffs DO NOT automatically engage BLD when wheel slippage occurs. I've found I MUST press the brake manually to get BLD engaged.

I was simply asking for "best practices" because there is a lot of confusion around the BLD.

 

[Htfan]

Here’s a somewhat related thread: https://www.jlwranglerforums.com/fo...action-control-brake-lock-differential.55438/

Great thread! This is one of the many I've read that got me interested in building my BLD knowledge.

 

[AcesandEights]

Best practice is not to engage the brake because it reduces the effectiveness of BLD. BLD requires individual braking of wheels, and if you engage the brake you reduce the speed and torque transfer.

 

[jludave]

my open diffs DO NOT automatically engage BLD when wheel slippage occurs.

Curious as to how you are determining this?

 

[Htfan]

Curious as to how you are determining this?

By personal experience on a recent trip in snow.

 

[jludave]

By personal experience on a recent trip in snow.

Sure, but what makes you think/believe it isn't working without your need to depress the brake pedal? I ask because your saying you need to do so essentially defeats BLD.

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