Automatic lockers

[MojaveLR3]

Hello everyone.

I've got a 69 Series IIa undergoing a rebuild and I'm having trouble deciding on lockers. Not so much a this-or-that brand issue but more of a locker design question.

So without getting too caught up in the particular locker brand squabbles, I would like to hear the arguments for and against lockers that are non-driver activated.

On many occasions I have heard comments against these types of lockers (TruTracs, Detroits, Kaisers) and the generic reason was something to the effect that, "I need to be in control of when it locks" and "there are times when it is better to NOT lock."

So what are the circumstances that could arise during general overlanding where you would find yourself wishing that you were NOT locked?

Generally, speaking, what are the arguments against the non-driver activated locker set-up. (not against the particular brands themselves)

 

[Metcalf]

I think it boils down to speed....

With an automatic locker a lot of the time you have to do things slower. Tight turning can take more time. You don't want to go too fast down a snowy/icy road in 4wd with front and rear lockers in 4wd. The bonuses to automatic lockers are hands off driving. You CAN get some disengagement without having to hit a button. There is no waiting and minimum wheel rotation needed to get both tires spinning. Cost is generally a big bonus too...auto lockers being cheaper. You do generally get more 'slop' in the drivetrain with auto lockers.

Selectable lockers are nice because you do and don't have to think about using them. You generally don't have to worry about them when driving around on a snowy icy road. You can keep your open diff and normal 4wd. You do however have to worry about turning them on and off during off road maneuvers, once they are locked you have a spool and turning is VERY limited, even more so than automatic lockers. Generally they also cost more and are somewhat more complex with more instances of failure because of this. Selectable lockers are also nice since you CAN leave them off and play on mild trails with open diffs. I think this is preferable to trying to do things in 2wd with a rear auto locker to make it more challenging....mostly since its easier on the drivetrain.

One of my favorite combos lately is an automatic locker front and rear along with a transfer case that allows the independent control of the front and rear axle. This way you can have front or rear wheel drive independently. This allows you to use only front wheel drive when trying to turn tight with a front locker....even more so than having the front disconnected in rear wheel drive only.

I have also been fairly impressed with the old Powr-Lok differential from Dana/Spicer. This is basically a 90% automatic locker...not just a limited slip as most people think. They are smoother than most dog-clutch style lockers....but they will not lock up 100% and they do need rebuild every decade or so.

 

[trump]

IMO Automatic lockers suck for all things road. There's a reason most road going vehicles do not have locked diffs (LSD's yes, but not a full-time locker.) They make vehicles unpredictable in low traction situations (ice, snow, and rain.) They also increase tire wear, and stress on the drivetrain (and many times, make a lot of noise.) If you plan on doing travel to and from trails on road, they wouldn't be my first choice.

Offroad they work great. The traction is there when you need it, BUT ...to me that creates another problem. A driver that doesn't know when that extra traction is required. I feel it's always better to stay unlocked until the need dictates. Just like I prefer to make my own gear selections with a manual transmission, I also like to select how many wheels get power.

I think this is preferable to trying to do things in 2wd with a rear auto locker to make it more challenging....mostly since its easier on the drivetrain.

I especially understand this statement after limping home on a trail this weekend in 2wd low and the rear locked. Lets just say a couple hill climbs got interesting. :smiley_drive:

 

[CA-RJ]

Let's say you're on a snowy/icy mountain road. As you accelerate out of a tight corner, the locker locks up and sends you into a slide.

 

[Nick02]

I love my Lock-Right and it is Daily driven behind my V8. I have have done it with 31's and 35's with 4.88's. I cant even notice it with my "regular" driving style. It's super quiet, you have to roll the windows down to hear it. I've never experienced any unloading or bucking.

If you hit the gas to hard in a corner it'll bark, and If I want it to lockup I floor it!
Does fine in snow/ice/rain, just dont go crazy.

 

[brained]

I have also been fairly impressed with the old Powr-Lok differential from Dana/Spicer. This is basically a 90% automatic locker...not just a limited slip as most people think. They are smoother than most dog-clutch style lockers....but they will not lock up 100% and they do need rebuild every decade or so.

Agreed. Powr-Loc in the rear (with an extra clutch to tighten it up), auto locker in the front w/manual hubs. Snowy, icy? Just lock in the uphill hub only.

 

[MojaveLR3]

Good info. Thanks.

"One of my favorite combos lately is an automatic locker front and rear along with a transfer case that allows the independent control of the front and rear axle. This way you can have front or rear wheel drive independently. This allows you to use only front wheel drive when trying to turn tight with a front locker....even more so than having the front disconnected in rear wheel drive only."

Excellent response and information Metcalf. The above scenario is exactly what I have been considering. I think with the addition of heavy duty axles, this could be an ideal set-up.

 

[mudbutt]

I have a '98 Jeep Cherokee.... ARB airlocker in the rear and a generic auto locker in the front.

I have only been in the snow 1 time and it was in Big Bear where they plow the snow off the roads. But then of course it snows some more before the plows come through again so the snow gets patchy in places...

It kinda sucked... I never really thought about using 4X4 because "most" of the roads were plowed and or dry.

But every once in a while I would come to a stop and hit a little snow or a wet spot and all hell would break loose. The locker would try and lock up, creating all kinds of steering issues, braking issues, and noise....

2 months or so after that trip I changed out the oil in the front diff and found a broken tooth from the locker in the bottom. Luckily it didn't look like it went through the R&P....

If you have the funds and a choice, a selectable locker would be better than an auto....

 

[MojaveLR3]

trump.

"Just like I prefer to make my own gear selections with a manual transmission, I also like to select how many wheels get power."

Thanks for the reply. This makes a whole lot of sense. However, I still struggle to define the scenario in which I wish I only had power to only one wheel on the axle. It's easy to "create" such a scenario for the sake of conversation but I just feel that your comment loses steam when restricted to normal, real world overlanding. I'm not saying that you're wrong, I just don't buy the 'I want control over my axles' mantra without logical supporting data.

 

[MojaveLR3]

Let's say you're on a snowy/icy mountain road. As you accelerate out of a tight corner, the locker locks up and sends you into a slide.

I believe that in this case, the driver got what was coming to him. :Wow1:

 

[trump]

trump.

"Just like I prefer to make my own gear selections with a manual transmission, I also like to select how many wheels get power."

Thanks for the reply. This makes a whole lot of sense. However, I still struggle to define the scenario in which I wish I only had power to only one wheel on the axle. It's easy to "create" such a scenario for the sake of conversation but I just feel that your comment loses steam when restricted to normal, real world overlanding. I'm not saying that you're wrong, I just don't buy the 'I want control over my axles' mantra without logical supporting data.

Did you not read the first part of my post then? For these reasons:

They make vehicles unpredictable in low traction situations (ice, snow, and rain.) They also increase tire wear, and stress on the drivetrain (and many times, make a lot of noise.) If you plan on doing travel to and from trails on road, they wouldn't be my first choice.

Also, on my particular truck having a full-time locker is an exercise in how often I enjoy changing CV's... might as well forget about turning.

 

[MojaveLR3]

Agreed. Powr-Loc in the rear (with an extra clutch to tighten it up), auto locker in the front w/manual hubs. Snowy, icy? Just lock in the uphill hub only.

Thanks brained.
I've put a lot of thought into this long before posting the question and ran lots of scenarios through my head. I have yet to find the show-stopper to my plan. Each situation has a pretty simple way to attack it just as you have so simply demonstrated.

 

[charlieaarons]

This is one of those threads with no right answer.
But living in a place with snow/ice 5-6 months/year:
I did fine in a F350 with Detroit rear/ARB front
A BJ40 set up identically
And a M37 with Lockrights at both ends ,but with power steering.
The rule for doing fine: use 4WD in snow and ice.
ARBs have had problems off and on over the years with compressors and air solenoids in my vehicles but an auto locker has never given me any trouble.
My Unimog came stock with fulltime 4WD and center, rear and front air lockers, i have no intention of changing of course.

Charlie

 

[MojaveLR3]

Did you not read the first part of my post then? For these reasons:



Also, on my particular truck having a full-time locker is an exercise in how often I enjoy changing CV's... might as well forget about turning.

Yes I did trump but I was already thinking ahead to the next part of the conversation and therefore, dismissed your comment since I felt that it didn't apply to where this is heading. Your point is well made and I don't disagree with any of it.

So to narrow the conversation down a bit, let's consider the actual locker that I am interested in. They are the Kaiser lockers made in Brazil which were recently shown at Expo 2010.

I'll try to avoid a crazy long post by making a few points.

A. If you google them and read what's being said on a lot of other forums, you will find a massive amount of misinformation being spread by people speculating and making assumptions. Most of what I have seen is wrong.

B. Most of the outcomes to the scenarios put forth so far in this thread would not be applicable to the Kaiser due to the nature of its operation.

C. Simply put, the Kaiser is ALWAYS locked. It would be more appropriate to call it an automatic un-locker rather than an auto-locker. There are no gears or clutches in the unit.

This unit works by un-locking any wheel that is driven by road friction. To put it another way, if the motive force driving the wheel is the drive shaft through the diff, then that wheel is obviously locked. (Driving straight down the street, both wheels are locked.) If the motive force driving the wheel is the friction on the tire from the surface, then that wheel is unlocked and free to spin as fast as dictated by forward motion. (turning left at the end of the street, the right side wheels will unlock)

Many people think that the Kaisers are just a Detroit in different skin. They are clearly not.

So the Kaisers have my attention at the moment and at $900 each, I am considering using one in each axle. I just need to get comfortable with the whole issue of being automatic.

Does any of the above change anything in your mind?

 

[MojaveLR3]

This is one of those threads with no right answer.
But living in a place with snow/ice 5-6 months/year:
I did fine in a F350 with Detroit rear/ARB front
A BJ40 set up identically
And a M37 with Lockrights at both ends ,but with power steering.
The rule for doing fine: use 4WD in snow and ice.
ARBs have had problems off and on over the years with compressors and air solenoids in my vehicles but an auto locker has never given me any trouble.
My Unimog came stock with fulltime 4WD and center, rear and front air lockers, i have no intention of changing of course.

Charlie

Great example. Thanks.
Reliability is at the top of my list of reasons to lean away from the driver controlled units.

Thanks.