Selectable diff locker debate (aftermarket).

John McVicker

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This scenario is a perfect example of why you want to be able to lock only the front axle with out having to lock the rear !!
Totally agree with this. Wire your ARB’s up separately from each other.
 

mudgudgeon

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Totally agree with this. Wire your ARB’s up separately from each other.

Same.

I find climbing an obstacle, the weight of the rig is biased toward the back. Locking the front helps with reduced traction on the front axle.
A lot of the time you can bump the rear up over the same obstacle once the front is over it without rear locker
 
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I think the scenario that people are leery of is being locked, driving forward, rocking back momentarily, then getting on the gas to go forward again, and having the mechanism unlock in that half tire rotation. So, when you got the gas again the kicker is momentarily unlocked.

I can picture it being a potential downside, but without playing with it in the bush, not sure if would actually translate to being a problem
That’s just it, there is speculation as to what might occur (base in part on theoretical evidence) but there needs to be more input from real world applications. From my simple observations, I have confidence that this unlocked situation will be a non issue. But can’t really say until better tested.
 

mudgudgeon

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That’s just it, there is speculation as to what might occur (base in part on theoretical evidence) but there needs to be more input from real world applications. From my simple observations, I have confidence that this unlocked situation will be a non issue. But can’t really say until better tested.

Well then, you're just gonna have to go wheeling man!! :hillbilly:
 

80t0ylc

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................It’s on my list to be able to just use the front locker instead of having to have the rear locker and the the front.
I never have liked the OEM locker dash switch! One of the reasons I was jazzed with my Harrops install. If you can believe it, there's some folks on this forum, mainly Toyota "purists"IMHO, that want their Harrops wired up to the "magic dial"! :rolleyes: This thread actually documents the process:


I started sounding off about it on page 3, post#56, but I guess some folks like their magic dial. One other advantage with both ARB and Harrop over OEM is you don't need the CDL locked to lock your axles. Not a big advantage for sure, but might come in handy to get you home if your CDL is acting up.
 
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my complaint with selectables isn't that they fail, it's that they can cause failure of other bits and pieces. Those other pieces are inner drive shafts, birfields and drive flanges to name a few.

Consider you are climbing a steep hill that is relatively flat and are faced with a small 3' ledge/rock to climb with the front right tire.

Fully locked with a selectable means that both rear tires and the front left tire will want the truck to move forward 3' while the front right will resist moving forward because it wants to climb vertical for that 3'. So you need to apply enough power to break the 3 tires on flat ground free of traction to allow the front right tire to climb the ledge.

Kaisers automatically adapt to that situation and allow the front right tire to rotate at a higher RPM. So at that point the front right tire is fully locked and the other 3 are at reduced torque based on the rotational speed of those tires.
If you have to defend your choice this much. It’s probably the wrong choice.

Everybody uses lockers for a reason. They work well
 

80t0ylc

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my complaint with selectables isn't that they fail, it's that they can cause failure of other bits and pieces. Those other pieces are inner drive shafts, birfields and drive flanges to name a few.

Consider you are climbing a steep hill that is relatively flat and are faced with a small 3' ledge/rock to climb with the front right tire.

Fully locked with a selectable means that both rear tires and the front left tire will want the truck to move forward 3' while the front right will resist moving forward because it wants to climb vertical for that 3'. So you need to apply enough power to break the 3 tires on flat ground free of traction to allow the front right tire to climb the ledge.

Kaisers automatically adapt to that situation and allow the front right tire to rotate at a higher RPM. So at that point the front right tire is fully locked and the other 3 are at reduced torque based on the rotational speed of those tires.
On this example of the one tire that encounters an obstacle, the forward pressure that the other 3 tires are giving the blocked tire helps it to grab traction, climb and pull it over the obstacle. In the rocks you generally have multiple obstacles simultaneously. So, with select-able lockers you have more "tools" in your "traction tool box" to continue progress and deal with whatever the trail presents. Reading the reviews, it sounds to me like the Kaisers are much like auto-lockers, so you're stuck with the performance they give with no chance to "turn them off" or on if the situation demands it. They might work better with part-time than with full time. Full time and select-able is a winning combination, IMHO.
 
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I regard my ARB as a ‘robust, time-tested locker” - but on the trail, I actually don’t like driving with the rear locked all the time, as the rear end always wants to push the truck straight ahead.

I’m looking forward to the findings of the OP once the diff is apart.
You don't have that anywhere near as bad with a "differentiating locker" such as the "automatic" lunchbox type or detroit. The Pushing straight effect that a spool or manual locker that acts lock a spool when locked is absolutely noticable on slick mud.
 
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Some people have installed a lunchbox type in the front and leave the rear open. This way you can drive in 2 wheel off road most of the time and on road and on slick roads without worry of spinning out. When you have to you shift into 4 wheel and have a very significant increase in traction. Perhaps a selectable locker in rear and automatic in the front? Drivability on slippery roads in 2 wheel, and running bad dirt roads in between mudholes or difficult areas and then shift in to 4wheel for the difficult points, and finally full lock all around for serious climbing or big bogs. Perhaps this gives the most possible selection of options for the type of traction and maneuverability needed for different situations................One thing I am fairly certain of is that a selectable locker does not give more traction or capability than a automatic locker such as detroit or luncbox type. The only advantage of the selectable is offering the ability to have a open diff rear end for driving on snowy/icy roads.
Lunchbox=greater traction combined with cheap price, Detroit=same traction with stronger design for Higher HP/lower gears combined with larger tires rock crawling but at a high cost similar to selectable locker but simpler/reliable, Selectable= best maneuverability unlocked but least stearability when locked, high cost and most complexity to install, When installed with a factory switch it can likely increase your resale value substantially??, Limited slip types=as expensive as detroit or selectable with better drivability/maneuverability than a locker in most situations, mostly as good as a locker in soft terrain, Requires skilled brake modulation and a automatic transmission to get you through rock climbing situations where one or 2 wheels are often off the ground. (I have had good success in serious off camber climbing situations with HMMWV's with torsen gleason "torque sensing" diffs front and rear when center diff locked in low range with medium throttle and easing off of brake to crawl forward or back. Similar to what you can do with a locker but it takes more practice.)
 
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ChaseTruck

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You don't have that anywhere near as bad with a "differentiating locker" such as the "automatic" lunchbox type or detroit. The Pushing straight effect that a spool or manual locker that acts lock a spool when locked is absolutely noticable on slick mud.
Yes, I am aware of the fact that with a Detroit neither wheel can spin slower than the ring gear, but one wheel can spin faster than the ring gear. But I don't have practical experience, coming from an American full-size with a part-time t'case. I've had good luck with ARBs going back to 1998, and my earlier response was more to the 'time-tested' part. Overall, I'd say that locker choice comes down to a matter of preference AND seat time. I'm in the planning stages for a dedicated lightweight rock crawler, and wondering whether I ought to put a Detroit in the front, with an ARB in the rear (just because I know what a rear ARB does).
 

baldilocks

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Yes, I am aware of the fact that with a Detroit neither wheel can spin slower than the ring gear, but one wheel can spin faster than the ring gear. But I don't have practical experience, coming from an American full-size with a part-time t'case. I've had good luck with ARBs going back to 1998, and my earlier response was more to the 'time-tested' part. Overall, I'd say that locker choice comes down to a matter of preference AND seat time. I'm in the planning stages for a dedicated lightweight rock crawler, and wondering whether I ought to put a Detroit in the front, with an ARB in the rear (just because I know what a rear ARB does).
Having had auto lockers and ARB’s, I completely understand why the selectable locker came about and has been wildly popular. A locker is a locker and a device that will allow differential wheel speed while power is applied is not a locker. All the talk about how this unit or that will allow a wheel to run free to facilitate the passing over an obstacle or around a tight turn escapes my understanding of traction. You know and appreciate the ARB units. I see no reason to use anything else in your crawler build. There is only locked or unlocked in my world, no in between. The only other way I’d go on a buggy dedicated to rocks would be spools.

Individual locker controls so that the front can be used solitarily to pull us around short turns or only the rear to force an over steer can be enjoyed only with selectable units.
 
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Some people have installed a lunchbox type in the front and leave the rear open. This way you can drive in 2 wheel off road most of the time and on road and on slick roads without worry of spinning out.

I had this setup for a bit and would not recommend it unless it's a dedicated, low-buck trail rig or you live somewhere with excellent road traction year-round (Los Angeles, Phoenix). Even if it's a trail rig, the jump from RWD to 4WD + semi-locked front is enormous. If you want it to be at all pleasant, you have to drive weird, like coasting through all turns. The moment you're on the gas, the front end wants to go straight.
 
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I had this setup for a bit and would not recommend it unless it's a dedicated, low-buck trail rig or you live somewhere with excellent road traction year-round (Los Angeles, Phoenix). Even if it's a trail rig, the jump from RWD to 4WD + semi-locked front is enormous. If you want it to be at all pleasant, you have to drive weird, like coasting through all turns. The moment you're on the gas, the front end wants to go straight.
Yeah. This sounds like a terrible idea
 

Broski

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I want to be in control of where and when my lockers become locked period
 
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this is a funny thread,
so many different driving conditions, truck usage, driver expectations to be able to give any kind of definitive blanket statement about locker setups

kind of like debating what kind of saw to own
I do realize the op's original question was a bit more consice than what lockers should i get though...........
 
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I had this setup for a bit and would not recommend it unless it's a dedicated, low-buck trail rig or you live somewhere with excellent road traction year-round (Los Angeles, Phoenix). Even if it's a trail rig, the jump from RWD to 4WD + semi-locked front is enormous. If you want it to be at all pleasant, you have to drive weird, like coasting through all turns. The moment you're on the gas, the front end wants to go straight.
I don't drive mine in 4wd on hard surface roads. I can imagine that would be an issue. I drove my samurai with lock rites with transfer in 2wd, but hubs locked on the road before and it was OK. The spartan locker in my BJ73 doesn't like this and is hard to turn even if the tcase is in 2 wheel. I think it is a bit to tight.
Off road on the trail in 4wd it is never an issue or problem with the truck wanting to go straight. I do however drive my rig and expect to steer it. If I can go 20 MPH or so I'll be in 2wd. I guess it depends on what you're used to.
 

Broski

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The thread got derailed in the first few pages!!!
It started out about the differences of selectable lockers, Air versus Electric
The OP tried to keep it track but the Peps weren't listening.
It was never about what type of lockers are best.
Of course people always tend to think whatever they have is the best😂🤣😁
 
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I don't drive mine in 4wd on hard surface roads

Hence the bit about excellent year-round road traction.

I have to pull into traffic from a turn in the rain for about half the year. Snow for at least a few days to weeks per year. I pulled the auto-locker when I determined I wasn't leaving anytime soon and I need access to at least intermittent, drivable 4wd on slick winter roads. I'll go back to full-time once I get front drive line vibes worked out.

Even with an SUV, drawers, and a 140 pound rear bumper, RWD traction still sucks for real-world winter use. I used to drive a long bed, 2wd pickup, so I'm familiar with the worst-case scenario, but I'd still rather have AWD on my 80.
 
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Having had auto lockers and ARB’s, I completely understand why the selectable locker came about and has been wildly popular. A locker is a locker and a device that will allow differential wheel speed while power is applied is not a locker. All the talk about how this unit or that will allow a wheel to run free to facilitate the passing over an obstacle or around a tight turn escapes my understanding of traction. You know and appreciate the ARB units. I see no reason to use anything else in your crawler build. There is only locked or unlocked in my world, no in between. The only other way I’d go on a buggy dedicated to rocks would be spools.

Individual locker controls so that the front can be used solitarily to pull us around short turns or only the rear to force an over steer can be enjoyed only with selectable units.
How a lunchbox type locker allows differentation: The pinion gear turns the ring gear which turns the carrier... The carrier pin turns with the carrier and turns the 2 halves of the lunchbox locker which lock into the side gears...The carrier pin pressing against these 2 halves forces them apart to lock into the side gears. When your outside wheel begins to turn faster than the inside wheel in a turn the half of the locker will move faster than the pin slightly and unlock from the side gear and "ratchet ahead sliding over the locking lugs". As soon as it is getting force from the carrier pin it will lock back in..........The lunchbox type will never allow either wheel to spin slower than the gear ratio. It will allow the outside wheel to turn faster....This is the differentation that gives you better steerability than an air, electric, or cable locker when locked. When you turn on slick terrain with a manual locker the outside wheel acts as a brake working against your turning the vehicle.

Detroit and lunchbox type is called a locker because it will not allow a wheel to slip or spin slower than driven. It will allow to ratchet ahead faster.
 

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