|09-20-2013 03:22 PM|
Why the limited slip isn't standard across the board is beyond me....
It's a must here in the land of winter ice and snow IMO, and most on lots never have the option.
|09-20-2013 03:07 PM|
|07-27-2013 05:04 PM|
Moab 24M Tru-Lok option trumps Trak-Lok?
|07-27-2013 04:08 PM|
Welcome to WF!
You can't have both at the same time. The Moab has an option for one or the other.
TJ Rubi's actually had a Locker with LSD. Best of both worlds.
|07-27-2013 03:47 PM|
|wrshultz||New member here and first post. I've been following this thread, plus the 2014 JK thread. I've also wondered why Jeep doesn't offer the Trak-Lok anti-spin (LSD) option on the Rubicon. At first I thought it wasn't available or compatible with the standard Rubi Tru-Lok, but noticed that Jeep did let both options be paired together on the rear of the 2013 Moab 24M limited edition. So, my original thoughts of not being compatible went out the window. Any comments about this factory combination? Thanks, Bill|
|07-25-2013 08:05 PM|
Trac Lok = Antispin/Limited Slip differential available on the Sport and Sahara
Rock Trac = 4:1 Rubicon transfer case
Tru Trac = Eaton/Detroit Limited Slip Differential
Command Trac = 2.72:1 Tranfer case in the Sport and Sahara
|07-25-2013 07:03 PM|
|Afrotango||hello all. What is "tru-lok"? is it a diff lock?|
|06-22-2013 06:21 AM|
Positrac- I don't know if you mentioned it already or not, but when you were driving in the snow, did the TCS light come on at all? If it was deep snow, it could just be the MTs had good traction the entire time, thus no TCS of any kind would be needed.
Also I think BLD had been used incorrectly this entire thread. From the discussion from the Jeep engineer referenced earlier , it mimics lockers not LSD. The owner's manual states TCS is the system that mimics LSD. TCS doesn't lock the brake, it just gradually applies it to get the wheels to spin at the same rate. If that's not working, it starts cutting the throttle. You're not guaranteed throttle reduction every time the TCS kicks in. In my mind its not much different then the clutch packs in the LSD in that slowing down the faster wheel so that both turn at the same time is key to getting traction back. The main advantage of the LSD is some of the friction from the clutch pack is being transferred to the slower wheel to speed it up while simultaneously slowing down the spinning wheel so that they meet at the same wheel speed sooner. Depending on well the TCS software is and how poor the LSD mechanicals are the effects could be negligible (sensors can detect wheel slip and other conditions much sooner than than centrifugal force can start working the LSD mechanics) . Maybe it's a 1/10th faster? 2 seconds? 1 nano second? Who knows? If it saved me a nano second of traction response and cost $300 and add one more thing to maintain, I might find that a debatable value. Since its hard to find someone who has had similar JK's ,one with, one without LSD, with the same conditions try each out and give real world feedback it's hard to say.
|06-21-2013 08:35 PM|
|06-21-2013 07:00 PM|
Big question to you is. Have you actually tried this all with your 2012+ Jeep Wrangler?
|06-21-2013 06:57 PM|
There is a reason why RWD vehicles have an LSD: because it gets busy at the back to put the power down and Stability Control is there to save your ass if you overdo it.
|06-21-2013 06:46 PM|
Didn't read beyond your mistake.
Look, friend, this isn't a competition on who is "right" or who is "wrong".
I'm giving you my real world experiences. What actually happens on the ground, despite what the "glossy" brochure says or the academic theses proffered.
Similar to the hysterics that a CAI on the jeep cannot do anything, without that person having ever removed the stock one and noted its purpose build sound muffling incarnation.
|06-21-2013 06:41 PM|
The owners manual is specific (even if consfusing) about this.
Normally, ESC and TCS are "on".
In 2WD, there are two modes avaiable.
ESC "on" (which includes TCS), and ESC "partial off" (which disables TCS and allows for wheel spin). You can't have wheel spin with BLD.
In 4L, there is only mode, ESC "off". In this mode, ESC is all the way off, the TCS is off except for the "limited slip" function (this would be BLD).
In 4H, there are three modes. ESC "on", ESC "partial off", and ESC "off". The work the same as above.
Being that all "city" driving will be done in 2WD. Your options are TCS "on" (normal) or TSC off (called ESC "partial off"....for wheel spin).
Again, whenver TCS is used, your ESC light will flash.
The problem with the Wrangler (for doing donuts) is that you either have BLD, Traction Control or ESC on. I don't think there is a mode that turns all of them off. However, I think that prior to 2011 (or 2012), it was easier to get the systems off (steering wheel dance). I'll have to check.
|06-21-2013 06:38 PM|
The fact that you're making this comparison between the TJ and JK means that you don't understand the different systems' functions and why that would be the case (ignoring the more important factors of weight and tires).
If you floored it on grass in your TJ w/ LSD you wouldn't move anywhere and both tires would spin.
If you floored it on grass in your JK (ignoring BLD) w/ LSD, you would start spinning both tires and throttle would be neutered and you'd be off on your way.
If you floored it on grass in your JK w/o LSD, you would spin a single tire, throttle would be neutered and you'd be off.
If you floored it on grass in your JK w/o LSD and w/ traction control off, you would spin the tire again, BLD would detect and start braking the spinning tire to deliver more power to the other wheel. As soon as that other wheel starts spinning, same thing again -- rinse and repeat, not nearly as graceful as a mechanical LSD because you're dealing with almost binary functionality on low traction surfaces, which is why BLD appears eclectic on soft surfaces and appears jerky on rocks because it's intent is to mimic lockers with full wheel braking on one side.
|06-21-2013 06:14 PM|
This is the murk or muck that needs to be clarified, and what I also want to know. Forget the marketing speak from Jeep. Is the application of the brakes being applied to a wheel that is losing traction, applicable at any speed and is that what is known as BLD.
Again all I can say is that with open diffs in both 4wd and 2wd in two monster winters, never once did I slide, slip lose traction in any usage of the vehicle whatsoever. And this coming from an old wrangler with LSD that couldn't move and inch in 2wd in glassed snow.
|06-21-2013 06:07 PM|
BLD is part of Traction Control, which is linked to ECS.
ECS is the part that reduces power to the engine (ERM reduced engine power as well).
Whenever Traction Control or ECS are used, the ECS light will show.
From the OM:
The “ESC Activation/Malfunction Indicator Light” also
flashes when TCS is active. If the “ESC Activation/
Malfunction Indicator Light” begins to flash during acceleration,
ease up on the accelerator and apply as little
throttle as possible. Be sure to adapt your speed and
driving to the prevailing road conditions.
2013 Wrangler Unlimited | Accident Avoidance Features | Jeep
Electronic Stability Control+is specially tuned for performance handling so you can switch it off. In addition, All-Speed Traction Control works in tandem with Electronic Stability Control. It has a special set of calibrations specifically for driving in 4LO. To help crawl over obstacles and during heavy articulation activity, it applies the brakes more aggressively and for longer duration than traction control.
The bolded would be your BLD...the actual programming.
If you are talking about normal driving and a spinning wheel being braked, that is Traction Control (I think you are calling that BLD...the process of a wheel being braked)...and when that happens, your ESC light will flash.
|06-21-2013 06:01 PM|
|positrak||Good test. While the tester is at it, check the rpms for both, which is higher which is lower in order to get going.|
|06-21-2013 05:53 PM|
In a typical scenario where 1 wheel can handle 50lbs (e.g., it's on ice) and the other needs 100lbs (on pavement) to begin moving you uphill, the BLD applies 50lbs of brake pressure to the 50lbs wheel -- thus total engine output would need to be 200 ft lbs.
In an LSD, say a 2:1, the wheel on ice gets 50 and the other gets 100 (maximum, for a 2:1). Engine output need only be 150ft-lbs for the same movement.
Someone go turn off DSC et al in their jeep except for BLD and pop the clutch with one wheel on the grass so we can see how long it takes to kick in. If it's longer than instantly, you have your answer to the above.
|06-21-2013 05:48 PM|
|NYJETS||At what mileage should the Diff fluids be changed? I have LSD so I guess I need a special fluid for that????|
|06-21-2013 05:47 PM|
|06-21-2013 05:45 PM|
|NYJETS||My head hurts|
|06-21-2013 05:19 PM|
Put is this way. BLD is on all the time, if you're turning a corner in the rain at 20 mph and the wheel slips, gentle pressure is applied. If you're off roading and at a 40 degree angle with two wheels on the ground, it will be applied aggressively which is abs level along with throttle reduction.
Unless this is completely incorrect BLD usage turning that corner at 20 mph in the rain and one wheel slips would have the system cut the throttle and brake hard where the abs invokes.
This is what needs to be cleared up. From experience I would suggest it is on all the time and gently applying the brakes as needed in any slip scenario. In a real slip scenario, full action will take place where brakes are applied to the abs level and the engine throttled.
|06-21-2013 05:04 PM|
There's info missing out there. From my experience:
1. Electronic Stability Control (ESC)
This system enhances directional control and stability of
the vehicle under various driving conditions. The ESC
corrects for over/under steering of the vehicle by applying
the brake of the appropriate wheel to assist in
counteracting the over/under steer condition. Engine
power may also be reduced to help the vehicle maintain
the desired path.
This is when the squiggly car icon lights up (flashes on and off) on the instrument cluster, the abs kicks in loud and the throttle choked. I had to push it really hard in deep snow to invoke it.
2.Traction Control System (TCS)
This system monitors the amount of wheel spin of each of
the driven wheels. If wheel spin is detected, brake
pressure is applied to the slipping wheel(s) to provide
enhanced acceleration and stability. A feature of the TCS
system functions similar to a limited slip differential and
controls the wheel spin across a driven axle. If one wheel
on a driven axle is spinning faster than the other, the
system will apply the brake of the spinning wheel. This
will allow more engine torque to be applied to the wheel
that is not spinning. This feature remains active even if
TCS and ESC are in either the “Partial Off” or “Full Off”
This is what I expect I have been experiencing of the past two winters, open diff, 2wd and 4wd with zero concern.
Out of all that muck, my understanding is BLD means just that, brake lock differential and the application of it as high lighted in the above.
The way everyone is talking BLD is only in the aggressive 1st scenario above, i.e. abs kicks in the vehicle is jerky, its loud and the engine gets throttled.
Doesn't sound right, BLD is on all the time, and if it is correct it is applied per 2. above gently as needed. What this violent combination of abs and engine throttling is called I don't think is BLD in the sense they are using it. BLD is in use but much more aggressively hence the panic use which is the abs kicking in, on normal use, just simple brake pressure is applied as warranted.
|06-21-2013 04:18 PM|
|06-21-2013 03:13 PM|
The BLD system is not a substitute for a fast acting eLSD. It is tuned for off-road 1 wheel with 0 traction conditions at slow speeds.
A mechanical LSD will never retard the throttle, which is why we are recommending it. The DSC will perform that operation if needed in the case where both wheels are slipping due to too much gas with the LSD.
|06-21-2013 03:00 PM|
Actually, the biggest difference maker in all of this is tires.
|06-21-2013 02:51 PM|
So for city driving it seems like either with or without LSD we are counting on the "computers" to keep the vehicle under control and moving forward. I've had 4x4's but never a Jeep or for that matter any 4x4 with all of this computer aided traction wizardry.
Am I right in assuming that "on the street" LSD would get you moving quicker than the computer will and will save wear and tear on the brakes but there is no situation where an open diff + computers will leave you stranded while a LSD + computers won't?
This almost makes me want to drive out to the ranch and dig a mudhole and do some experimentation...(except we would need some rain for mud and that ain't happening).
|06-21-2013 02:50 PM|
I think it has much more to do with a comprehension issue.
Oh and by the way most minivans are front wheel drive.
This is like trying to teach a Flight attendant how to fly the plane.
Lastly you are correct BLD is just like anti-spin.
Jeeps are just like minivans.
And welcome to our planet.
|06-21-2013 02:43 PM|
|DC Dennis||All of that is the exact same stuff, traction control applications with different programming applying to different situations. Stability control, Anti-lock brakes, and traction control/eLDS/BLD/etc. There will be retarded throttle and applied brakes in each. The only traction control programing that does not really throttle back or apply the breaks is on high performance extics with launch control, but even that retards the engine to limit wheel spin, but gives you a 0-60/0-100 time that no human is fast enough to pull off.|
|06-21-2013 02:26 PM|
|panthermark||The biggest benefit of LSD is that it is straight up mechanical. So the goal is basically to get traction before the nanny systems start to kick in. And if the nanny systems do kick in, they are less invasive because you already have torque transfer in place.|
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