Selectable diff locker debate (aftermarket).

[trinydex]

I considered the comment on the 2 replacements, too. But like @trinydex mentioned, the author is clearly an ARB believer, so he could be lying or fed bad info from the Harrop rig owner. It could even be the installer is totally inept and keeps screwing up the installs.

not to cast aspersions, but it's also the case that not everyone who goes on a guided off-road trip is a wrencher. some people have money and they believe what they're told about stuff they don't have expertise in.


all these are just data points. I'm just trying to get the best picture I can get before I spend my money.

 

[DivByZero]

I currently have a Harrop Elocker in bits in my garage I've been slowly chipping away at rebuilding. Bought it broken from a mechanic, looks like user error caused the failure (cross shaft failure, either from not enough diff oil, or spinning a wheel too long for extended periods). I've had a lot of time to closely examine the mechanism, and honestly, these lockers are dead simple. I'll do a thread on the rebuild when I'm done so you guys can see for yourself, but I've seen the same videos, and I'm convinced they had an electrical problem preventing engagement.

Unless the locker is physically damaged in some way, as long as power is reaching the magnet, IF it unlocks at all (which will only happen if the driveline ends up unloaded), it WILL relock within a maximum of about 40 degrees of wheel rotation. If anyone's locker does otherwise, the locker is either physically damaged, or they have an electrical issue preventing them getting 12v to the magnet. Anyone claiming otherwise should be able to provide a technical explanation and demonstrate exactly how and why this occurs. I have yet to see that. Here's a video from harrop talking about this issue specifically, demonstrating the same kind of unit I currently have in peices:

 

[mudgudgeon]

I currently have a Harrop Elocker in bits in my garage I've been slowly chipping away at rebuilding. Bought it broken from a mechanic, looks like user error caused the failure (cross shaft failure, either from not enough diff oil, or spinning a wheel too long for extended periods). I've had a lot of time to closely examine the mechanism, and honestly, these lockers are dead simple. I'll do a thread on the rebuild when I'm done so you guys can see for yourself, but I've seen the same videos, and I'm convinced they had an electrical problem preventing engagement.

Unless the locker is physically damaged in some way, as long as power is reaching the magnet, IF it unlocks at all (which will only happen if the driveline ends up unloaded), it WILL relock within a maximum of about 40 degrees of wheel rotation. If anyone's locker does otherwise, the locker is either physically damaged, or they have an electrical issue preventing them getting 12v to the magnet. Anyone claiming otherwise should be able to provide a technical explanation and demonstrate exactly how and why this occurs. I have yet to see that. Here's a video from harrop talking about this issue specifically, demonstrating the same kind of unit I currently have in peices:

Great video. That puts it pretty clearly and simply how they work.

Shame they are so damn pricey!

 

[mudgudgeon]

Is the one you have front or rear?

 

[DivByZero]

Is the one you have front or rear?

Front. Was fitted to the rear of a Hilux. Plan is to get a rear one to match when I can justify the cost.

 

[BILT4ME]

I currently have a Harrop Elocker in bits in my garage I've been slowly chipping away at rebuilding. Bought it broken from a mechanic, looks like user error caused the failure (cross shaft failure, either from not enough diff oil, or spinning a wheel too long for extended periods). I've had a lot of time to closely examine the mechanism, and honestly, these lockers are dead simple. I'll do a thread on the rebuild when I'm done so you guys can see for yourself, but I've seen the same videos, and I'm convinced they had an electrical problem preventing engagement.

Unless the locker is physically damaged in some way, as long as power is reaching the magnet, IF it unlocks at all (which will only happen if the driveline ends up unloaded), it WILL relock within a maximum of about 40 degrees of wheel rotation. If anyone's locker does otherwise, the locker is either physically damaged, or they have an electrical issue preventing them getting 12v to the magnet. Anyone claiming otherwise should be able to provide a technical explanation and demonstrate exactly how and why this occurs. I have yet to see that. Here's a video from harrop talking about this issue specifically, demonstrating the same kind of unit I currently have in peices:

As it shows in that video, the pin and ramp assembly is exactly what is causing the disengagement at the "neutral" position between forward and reverse.

He even demonstrates it during his forward / reverse thing at 1:44. He even states "backwards, then forwards and it is RELOCKED again". This indicates that it is UNLOCKED. He also states that is may be 6" of tire movement. This is tire diameter dependent. The larger the tire, the longer the throw. The more there is more torque required and has a higher chance of breaking things.

If you are gouging on it FWD to REV, that pin sliding back and out, then ramp up and back in, is the exact problem where the buildup in inertia will break things.

Eaton's literature even states it will unlock between FWD and REV.

Mind you, I have been wanting these e-lockers.
I don't WANT an air compressor or anything extra. Hell, I even considered cable lockers until I figured out that I may not be able to unlock them manually if in a tight situation.
I have used Eaton limited slip units and currently have a Detroit Locker in our son's 70 GMC K2500.

Eaton has improved the durability by going from 2 pinion to 4 pinion support, which is more like that on the Detroit.

The Detroit can handle big HP and all kinds of abuse, but that comes with an expense of not being "nimble" and able to unlock. In fact his is locked at the slightest acceleration and it chirps tires on EVERY corner.

The LC does not have big HP. Maybe there's not enough HP and Torque to have the E-Locker ramp thing be a problem.

I'm going to wait for more conjecture and more folks to have them and see what kind of failures are really out there.

On my LC, I want LONGEVITY and DURABILITY. This is why we can get 500K miles out of these trucks. They are not over-HP or high-revving trucks out of the factory.

I've done the high HP mods and have torn up MANY differentials, at least 4 of them being the Eaton LS type. I don't want to go down that path again.

 

[80t0ylc]

As it shows in that video, the pin and ramp assembly is exactly what is causing the disengagement at the "neutral" position between forward and reverse.

He even demonstrates it during his forward / reverse thing at 1:44. He even states "backwards, then forwards and it is RELOCKED again". This indicates that it is UNLOCKED. He also states that is may be 6" of tire movement. This is tire diameter dependent. The larger the tire, the longer the throw. The more there is more torque required and has a higher chance of breaking things.

If you are gouging on it FWD to REV, that pin sliding back and out, then ramp up and back in, is the exact problem where the buildup in inertia will break things.

Eaton's literature even states it will unlock between FWD and REV.

Mind you, I have been wanting these e-lockers.
I don't WANT an air compressor or anything extra. Hell, I even considered cable lockers until I figured out that I may not be able to unlock them manually if in a tight situation.
I have used Eaton limited slip units and currently have a Detroit Locker in our son's 70 GMC K2500.

Eaton has improved the durability by going from 2 pinion to 4 pinion support, which is more like that on the Detroit.

The Detroit can handle big HP and all kinds of abuse, but that comes with an expense of not being "nimble" and able to unlock. In fact his is locked at the slightest acceleration and it chirps tires on EVERY corner.

The LC does not have big HP. Maybe there's not enough HP and Torque to have the E-Locker ramp thing be a problem.

I'm going to wait for more conjecture and more folks to have them and see what kind of failures are really out there.

On my LC, I want LONGEVITY and DURABILITY. This is why we can get 500K miles out of these trucks. They are not over-HP or high-revving trucks out of the factory.

I've done the high HP mods and have torn up MANY differentials, at least 4 of them being the Eaton LS type. I don't want to go down that path again.

After reading through your post, you repeatively refer to "big HP" and make comments how the Detroit locker can handle the stress. Yet, in your last 2 sentences mention that you've torn up many differentials, some of them being Eaton LS type. My question is, what kind of driving do you do that's caused this? The reason I'm asking is that IMHO, the Harrop E-locker is not designed for competition type of driving and would not be a good choice if that's what you do.

 

[trinydex]

I currently have a Harrop Elocker in bits in my garage I've been slowly chipping away at rebuilding. Bought it broken from a mechanic, looks like user error caused the failure (cross shaft failure, either from not enough diff oil, or spinning a wheel too long for extended periods). I've had a lot of time to closely examine the mechanism, and honestly, these lockers are dead simple. I'll do a thread on the rebuild when I'm done so you guys can see for yourself, but I've seen the same videos, and I'm convinced they had an electrical problem preventing engagement.

Unless the locker is physically damaged in some way, as long as power is reaching the magnet, IF it unlocks at all (which will only happen if the driveline ends up unloaded), it WILL relock within a maximum of about 40 degrees of wheel rotation. If anyone's locker does otherwise, the locker is either physically damaged, or they have an electrical issue preventing them getting 12v to the magnet. Anyone claiming otherwise should be able to provide a technical explanation and demonstrate exactly how and why this occurs. I have yet to see that. Here's a video from harrop talking about this issue specifically, demonstrating the same kind of unit I currently have in peices:

I think I'll end up with a Harrop up front, but I'm still interested in the theory of what's going on in these unlocking videos.

you're saying the mechanism is dead simple.


we don't know the true conditions of what's happening in the video, maybe the guy just didn't press the button, maybe there's bad wiring, who knows.

in the case that we are trying to steel man the other side's argument, what could potentially cause the failure or delay of reengagement of the lock after a roll back or roll forward situation?


is there a way that case deflection or loading of the gears can prevent the pins from shifting the locking plate into place? or maybe deflection causes the surface of the electromagnet and the cam actuating surface to not mate? or maybe with high wheel speed before positive locking the electromagnet doesn't positively engage to grab the cam actuating surface?

just trying to explore possible explanations.

it clearly doesn't get stuck in lock ever. it just seems like it may get stuck unlocked or have a prolonged transition to locked.

 

[Czechmate]

My experience is that if you have some driveline loading then it seems to remain locked in forward/backward shifting situations. Also, I haven’t felt, noticed or observed an unlocked state while testing this on flat loose gravel parking lot doing figure 8’s. But here again, the figure 8’s tend to create some drivetrain binding or loading as well. I don’t doubt it may be there in some form in some condition, I just haven’t detected it yet.

 

[trinydex]

My experience is that if you have some driveline loading then it seems to remain locked in forward/backward shifting situations. Also, I haven’t felt, noticed or observed an unlocked state while testing this on flat loose gravel parking lot doing figure 8’s. But here again, the figure 8’s tend to create some drivetrain binding or loading as well. I don’t doubt it may be there in some form in some condition, I just haven’t detected it yet.

from the "issue" videos it seems like it happens when the drive line is pointing all which ways and there's not constant progress, there's a stop, then a reattempt and that's where it seems things are not meshing up.

 

[BILT4ME]

After reading through your post, you repeatively refer to "big HP" and make comments how the Detroit locker can handle the stress. Yet, in your last 2 sentences mention that you've torn up many differentials, some of them being Eaton LS type. My question is, what kind of driving do you do that's caused this? The reason I'm asking is that IMHO, the Harrop E-locker is not designed for competition type of driving and would not be a good choice if that's what you do.

I'm not referring to anything along the line of competition. Sorry I wasn't more clear.

When I say "big HP" it is subjective. Big HP used to be 350+HP "back in the day". Nothing in the 1000+HP, although the Detroit is made for that kind of range.

I was tearing up Eaton LS diffs with a 1969 Chevy K10 half ton with a 375 HP 350CID, 4V, 4.11 gears, a 4 speed (SM365), Rockwell T221 Tcase, 33x12.50-15 tires, driving in a city, catching puddles from rogue sprinklers, in 3rd gear while going around a corner. Inside tire would catch the water, spin, then lock up and blow up things. not something that should have had enough oomph to blow up a diff. It's not like I was WOT and intentionally hammering it.

I also had one blow up that I was in a plowed field, standing water, pushing mud over the diffs, forward and back a lot. That was WOT, hard fwd, hard rev.

My truck was built and used for farm use. Lots of pulling, mud, work, hauling, and playing when I had the chance. I was not a stupid hard throttle guy all the time because that WOULD break things. I had friends that way and they were blowing up 3/4T diffs and front axles.

Yes, technology has improved over the years. Eaton even stated they have "new technology" in the Harrop E-Locker which is the four pinion setup. That's what the Detroit uses. It spreads out the load to four pinions instead of two. it's not "new technology" it's just new to the H-E-locker.

No, my 4.5L stock LC will not create enough to blow things up by HP, but if I get carried away and pissed off when I'm stuck, the last thing I want to do is blow up a diff because of a design "flaw". Yes, I swear sometimes I can break a hammer.

I have pulled loaded semi's out of ditches, out of snow covered parking lots, and out of serious uphill situations with that old truck. Low range, first gear, and easy on the clutch can get you a long ways. My LC is extremely pale in comparison, but it's a different tool for a different job. I miss the old truck, but I love my LC.

As I have said before, GM created a very similar situation with their self-locking front hubs in the mid-70's- 80's. This frequently added up to exploded front hubs. Similar (not exactly the same) situation.

The ARB does not operate that way. The arb is more like the Detroit, but with an actuator that locks them together and stays that way. I just don't like the dependence on the compressed air and the additional system I would have to add to my truck.

 

[DivByZero]

As it shows in that video, the pin and ramp assembly is exactly what is causing the disengagement at the "neutral" position between forward and reverse.

He even demonstrates it during his forward / reverse thing at 1:44. He even states "backwards, then forwards and it is RELOCKED again". This indicates that it is UNLOCKED. He also states that is may be 6" of tire movement. This is tire diameter dependent. The larger the tire, the longer the throw. The more there is more torque required and has a higher chance of breaking things.

If you are gouging on it FWD to REV, that pin sliding back and out, then ramp up and back in, is the exact problem where the buildup in inertia will break things.

Eaton's literature even states it will unlock between FWD and REV.

Mind you, I have been wanting these e-lockers.
I don't WANT an air compressor or anything extra. Hell, I even considered cable lockers until I figured out that I may not be able to unlock them manually if in a tight situation.
I have used Eaton limited slip units and currently have a Detroit Locker in our son's 70 GMC K2500.

Eaton has improved the durability by going from 2 pinion to 4 pinion support, which is more like that on the Detroit.

The Detroit can handle big HP and all kinds of abuse, but that comes with an expense of not being "nimble" and able to unlock. In fact his is locked at the slightest acceleration and it chirps tires on EVERY corner.

The LC does not have big HP. Maybe there's not enough HP and Torque to have the E-Locker ramp thing be a problem.

I'm going to wait for more conjecture and more folks to have them and see what kind of failures are really out there.

On my LC, I want LONGEVITY and DURABILITY. This is why we can get 500K miles out of these trucks. They are not over-HP or high-revving trucks out of the factory.

I've done the high HP mods and have torn up MANY differentials, at least 4 of them being the Eaton LS type. I don't want to go down that path again.

I talked about the lock-unlock behaviour in my own post. I wasn't saying it doesn't exist, but if you'd read my post and watched the harrop video, you'd see that that behaviour in no way matches what is claimed or shown in that video. If what you want is as you say more real world feedback, read in another thread on this forum from here:

OEM E-Lockers vs. Harrop

What is the current go-to place to order and/or have the Harrops installed? Are they called Harrop? Or Eaton? I see both brands being thrown around so I want to make sure we are talking about the same product. Ideally I’d like to just remove my third members and ship them out to an experienced...

forum.ih8mud.com

 

[mudgudgeon]

As it shows in that video, the pin and ramp assembly is exactly what is causing the disengagement at the "neutral" position between forward and reverse.

He even demonstrates it during his forward / reverse thing at 1:44. He even states "backwards, then forwards and it is RELOCKED again". This indicates that it is UNLOCKED. He also states that is may be 6" of tire movement. This is tire diameter dependent. The larger the tire, the longer the throw. The more there is more torque required and has a higher chance of breaking things.

Saying 6" of tyre rotation is kind of meaningless. The thing that stays constant regarding of tyre size is how many degrees of rotation is needed to ramp up.

One thing they alluded to, but didn't go into was it's not simply tyre rotation that's required, its differential rotation across the spider gears.
This means after rolling back, the locker disengages. After powering forward, if both tires spin at almost the same rate, there may not be enough torque differential to ramp up the pin and lock the mechanism straight away.
How many feet do you drive before there's enough torque differential to lock it?
Will it "crash lock"?

I've had two landcruisers with oem lockers. Turning then on, they function similarly in so much as you need enough differential rotation in the diff centre to line up the locking dog. Is a coarse mechanism, and often means you drive dozens of feet through an obstacle before a tire spins enough for the locker to crash lock under load.
After hundreds of cycles off road, never had any indication this was a problem. Sometimes they crash lock HARD! Other times it'll just be a click.
Having said that, once locked, they stay locked until you disengage them and there's no torque loading on the driveline.
Sometimes they won't release mid obstacle when you want to be able to turn them off to steer tightly, so you end up fighting a locked front axle.

ARBs will be my go to eventually. And I have the OEM locked centres from my previous 80 sitting in the garage.

 

[DivByZero]

ARBs will be my go to eveventually.

Not going TJM Pro's? That'd be my pick if I was going air.

 

[mudgudgeon]

Not going TJM Pro's? That'd be my pick if I was going air.

Possibly. Would have to weigh the pros and cons.

Thoughts?

 

[DivByZero]

Possibly. Would have to weigh the pros and cons.

Thoughts?

The TJM pro's don't pressurise the whole diff, just an internal section of the locker assembly. Simple operation, just as strong or stronger than the ARBs, and much less potential for air leaks. Worth the bit extra IMO.

 

[mudgudgeon]

Yeah, it's ages since I looked at the differences. Will have to look into them again

 

[DivByZero]

One thing they alluded to, but didn't go into was it's not simply tyre rotation that's required, its differential rotation across the spider gears.
This means after rolling back, the locker disengages. After powering forward, if both tires spin at almost the same rate, there may not be enough torque differential to ramp up the pin and lock the mechanism straight away.
How many feet do you drive before there's enough torque differential to lock it?
Will it "crash lock"?

While you're right about that, if both wheels are spinning at the same rate, whether the locker was engaged or not, there'd be no effect. By definition, a locker only does anything if the wheels want to spin at different rates. If both wheels are spinning flat out, but at the same rate, the spider gears are idle and there's no torque differential between the two. Crash lock is only an issue when there's a torque differential, so the total amount of force you can apply is limited to the torque differential you can create within a 40 degree or so rotational difference between the two tyres.

Or to put it in another way, if both wheels are spinning, no locker on earth is going to help you.

 

[mudgudgeon]

Or to put it in another way, if both wheels are spinning, no locker on earth is going to help you.

Agreed. Until one is not.

With OEM lockers, there's many times I've hit the switch on approach to an obstacle I expect I'll need lockers.

Sometimes one wheel will spin enough to allow the dogs to align, and lock fairly quickly ( loose surface). Sometimes, I've driven all the way through an obstacle and not had enough wheel spin to allow the locker to engage at all.
This seems to happen more with the rear locker. I figure steering action gives more differential rotation. That and the front is often un-weighted when crawling up an obstacle.

I found if the lockers were truly needed, they would always engage, then stay locked.

Sometimes I'd be sweating bullets waiting for the locker to engage because I was sure I would need it, and you're consciously waiting to hear it engage

 

[Dave 2000]

As per my Avatar, I used a Discovery in competitions, that had the ARB's front and rear, I know the compressor adds a small additional work to fit, but the lockers worked brilliantly. It was a long while ago, but I never broke one proper, but did have a issue with air leaking from the rear differential 'O' ring, that might have been an install cock up? The occasional puff of oil from one of the solenoids up front by the compressor more a nuisance than anything, but apart from it giving on board air (fit a reservoir though), the lockers were great and never let me down, and I assure you they got more than their fair share of stick!

I am not associated with ARB now or back then, but back circa 15 years they were the 'go too option' in my opinion. My present 80 VX came with the three stock lockers and they are great, whilst rarely used in anger, when properly cleaned out they lock/unlock with ease....small caveat, on one ocassion the front refused to lock when I needed it to to make a long steep hill climb but with limited run up, I rotated the steering lock to lock a few times and it came in and locked, that was the one single time it gave issue until recently, I have not used them properly for awhile, the rear still works but sounds like a cement mixer when it engages, the front is no longer engaging at all, with the front axle about to be overhauled it will get sorted then.

Only an opinion, but many are looking to save money and buy a bigger set of wheels and tyres, they look better than the ARB that people can't see.

ARB are expensive but if installed carefully they are brilliant!

Regards

Dave.