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  #37  
Old 10-06-2011, 03:53 PM
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Re: locking differentials

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Originally Posted by JRoll1ns View Post
the brake lock is good because its simple that's why it is used in Military hmmmwv's. Few people actually new that if you managed to get one stuck (HMMWV that is) all you had to do was put it in lo lock and stand on the brakes while operating the throttle ( no abs or computer). If you did that those things would claw themselves out of just about anything.


thats pretty awesome... does that work with the QTII, you think??
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  #38  
Old 10-06-2011, 04:15 PM
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Re: locking differentials

I think that the ABS and the computer take care of the "standing on the brake" part. There are no computers in military HMMWV's so there is nothing to sense wheel slip. So you have to physically sense the slippage and physically engage the brake lock. I think that the QTII uses the wheel ring sensors to sense the wheel slippage and the abs proportioning block to direct fluid to the wheel it wants to send power to. So I think that by applying the brakes you would actually hinder the brake locks ability to work. I am just guessing and assuming that is how the QTII works automatically.
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  #39  
Old 10-06-2011, 04:36 PM
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Re: locking differentials

I believe the standing on the brake is used on mechanical torsen style locking differentials, using the brake encourages the binding function of the differential causing a lockup. So, true, this was not a great compairison, compairing mechanical lsd's to abs module applying brakes at slipping wheels.
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  #40  
Old 10-06-2011, 06:03 PM
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Re: locking differentials

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Originally Posted by DGoral31 View Post
for the record ... i have JeepCoop on my ignore list... im not sure what he's saying but just know that its probably some sort of bash or idiotic comment against me and i apologize because it probably has nothing to do with the topic of this thread.
Nope, just stating the truth, you got stuck! Being stuck and having lockers is kinda relative. Plus I don't bash, I just speak the truth!
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  #41  
Old 10-06-2011, 08:48 PM
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Re: locking differentials

You can intelligently use the foot blake on any non locker or ABS equiped vehicle to slow the spinning wheel and transfer torque axross the axle to the loaded wheel.
It wworks particularly well with LSD diffs, a sharp stab at the brake pedal can actually get the LSD to work better, lock harder.

I used to use this method all the time in my Mitsubishis and Landcruisers.
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  #42  
Old 10-06-2011, 09:28 PM
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Re: locking differentials

All I had in my XJ was a factory limited slip and disconencted front sway and I could anywahere the big boys would go.

I think driving skill is as important as equipment.
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  #43  
Old 10-06-2011, 09:36 PM
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Re: locking differentials

very true
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  #44  
Old 10-06-2011, 09:58 PM
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Re: locking differentials

good call misfit, i took my XJ everywhere too... im probably just being picky... i barely off road enough as it is to worry about lockers haha... i like using my money for other things these days than just dumping into fixing things on my jeep!


Marlin- nice of you to chime in ol' chap!! how ya been!?
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  #45  
Old 10-08-2011, 11:09 PM
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Re: locking differentials

Quote:
Originally Posted by JRoll1ns View Post
the brake lock is good because its simple that's why it is used in Military hmmmwv's. Few people actually new that if you managed to get one stuck (HMMWV that is) all you had to do was put it in lo lock and stand on the brakes while operating the throttle ( no abs or computer). If you did that those things would claw themselves out of just about anything.
HMMWV's do not have any kind of brake lock. They have torsen limited slip differentials. It is a gear driven type of limited slip and very effective. But it is not similar to our WK's brake lock traction system. As Marlin said, using the brakes with a limited slip helps them to engage, and that is why your method worked.
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  #46  
Old 10-09-2011, 04:12 PM
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Re: locking differentials

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Originally Posted by 2005JGC View Post
I have been keeping my eye open for a wrecked QDII grand for some axle assemblies... I figure wire up a switch or 2 switches (F+R or both on one) and it will lock the clutch packs up. Ultimately my brake lock function works very well, being an 05 I cannot disable my esp like the newer models and this thing is just plain boring in the snow, I can hardly get it sideways slapping the throttle with the wheel at lock, on fresh snow from a stop (infact I think I gaveup trying last year). The QTII is very functional, I think if I could get a decent deal on some QDII axles it would be that much more comefort offroad... plus I would imagine it would keep my abs actuation at bay which annoys the crap out of me ha ha.
There is a guy on another forum who has tried this. It isn't as simple as you might think. He was not able to get the diff to lock by just applying power. Turns out these things do not just lock and unlock like a typical locker (which is why Jeep calls them limited slips and not lockers). They operate by a lock percentage. They can go anywhere from 0% or an open diff to 100% like a locked diff. And it all depends on the input voltage from the computer. I am not sure if he ended up figuring something out or not, because my computer crashed and I lost the link and now I don't remember what sight it was.

Also, I could be wrong but I remember reading somewhere that the ESP system has been changed a few times. There is even a variation in the 05 systems. Some of the early ones were a straight on/off were as later they changed it to on/mostly off. Then you have te newer systems which are on/mostly off/off. Which makes sense since I have an early 05 and when I turn the ESP off it never bothers me no matter what I make my Jeep do.

Lastly Jeepingib is correct about the HMMWV. They do not have a brakeing traction system, it is all differential. You just use the brakes to engage the diffs. In fact, you don't even need to come to a stop to use them, once you get comfortable with the system you can lock them on the roll.

Oh ya! I almost forgot, there are two guys that I know of that have installed an ARB air locker in the rear 10 bolt 8.25!
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  #47  
Old 10-09-2011, 04:41 PM
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Re: locking differentials

I dont have first hand knowledge from having tried this, but I undersand the solenoids in the diffs are pwm to give an apply percentage, but all 100 duty cycle is is direct battery voltage (no on-off pulsing, just on)... so at least in theory applying battery voltage to the solenoid will block the bypass passage and apply full pressure to the clutch pack. All that is happening is when no power is applied to the solenoid there is a clutch bypass that all pumped fluid from the gerotor pump does just that, bypasses the clutchpack, as voltage is applied to the solenoid it plugs the bypass and forces the pressurized fluid to the clutches, while it has much greater integration and making my non QD rig control it would be impossible, wiring in circuits to the axles for switched battery voltage would be very simple. Jeep also calls them limited slips because they are just a clutched device, there is no dog clutch or something that will ensure a solid lock, its just a clutch pack that given enough torque will still slip power to the wheel with the least traction. Ultimately if one really cared you could make 2 pwm controllers both controlled by a knob that you could dial up the apply percentage... realistically if they are not computer controlled the only real use they would serve would be on and off as changing around the apply force in a way to manage torque while negotiating would be boarderline impossible.

I am more than open to being proven wrong, I would actually appreciate it as 1500 dollars for used axles that are expensive paperweights to me would be pointless, but I would be VERY interested to see what problem this guy had, the function and design is very simple but as such I would not be supprised if I am overlooking a key componenant

I also have a decently early build 05 (being built december 04 iirc), and esp on or off made little difference in the snow covered parking lot last year .
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  #48  
Old 10-09-2011, 06:59 PM
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Quote:
Originally Posted by jeepingib View Post
HMMWV's do not have any kind of brake lock. They have torsen limited slip differentials. It is a gear driven type of limited slip and very effective. But it is not similar to our WK's brake lock traction system. As Marlin said, using the brakes with a limited slip helps them to engage, and that is why your method worked.
I stand corrected, and I apologize for spreading mis information. I did assume that since the brake application worked it was the same setup. Again sorry

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