auto lockers vs selectable cross axle

Submitted: Monday, Jan 14, 2008 at 20:08
ThreadID: 53489 Views:2052 Replies:5 FollowUps:5
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Hi all,

What are the pro's and cons of using each of these systems and would it be advisable or practicle to fit auto lockers to the rear axle and selectable cross axle lockers to the front.

cheers
baldman
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Reply By: Robin Miller - Monday, Jan 14, 2008 at 21:12

Monday, Jan 14, 2008 at 21:12
For ultimate performance across all conditions I would rate the selectable cross axle type is the best Baldman.
However it doesn't perform best under all circumstances and under all driveline configurations.

Assuming the once standard part time 4wd system with lockable hubs.
The auto locker can be very good in non-slippery conditions but after using both in Patrols I have no doubts that ARB type is most practical.

The ability to turn it off on slick surfaces has saved me more than once and some of my most memorable 4wd moments have been spent understeering off a track due to the inability to de-select the automatic type.

While I don't know what car you refer to , generally speaking a rear auto and a front selectable is an acceptable combination


Robin Miller
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Follow Up By: baldman - Monday, Jan 14, 2008 at 21:26

Monday, Jan 14, 2008 at 21:26
Thanks for the advice Robin.

Due to $$$ I will probably be purchasing a rig with manual hubs. The type or model is still undecided.

My assumption was that whilst attempting the more difficult parts of the track the auto locker would engage and assist when needed and a front ARB type would also be used when necessary.

By having an ARB type on the front I was hoping that this would not impede my steering ability on smooth or slick tracks.

Plus the money saved by going this way would go towards a winch.

thanks
Baldman


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Reply By: Eric Experience - Monday, Jan 14, 2008 at 21:21

Monday, Jan 14, 2008 at 21:21
Baldman.
Selectable lockers do make steering difficult where autolockers allow almost normal steering. Personally I prefer auto lockers both ends. I have vehicles with both set ups and the autolockers are great because there operation is almost transparent to the driver while the solid lockers require input and when the steering does not respond the time taken to release them can be the difference between missing the tree and hitting it. Eric.
AnswerID: 281640

Follow Up By: baldman - Monday, Jan 14, 2008 at 21:30

Monday, Jan 14, 2008 at 21:30
Thanks Eric.

I reckon the input part is the area that will cause more problems. Being new to it I reckon I could get so excited that I would probably forget to switch on the lockers.

thanks for the advice

Baldman
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Follow Up By: Member - Doug T (FNQ) - Monday, Jan 14, 2008 at 22:08

Monday, Jan 14, 2008 at 22:08
Eric
Your spot on with those comments, Auto both ends, always working 100% when needed
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Reply By: splits - Monday, Jan 14, 2008 at 22:41

Monday, Jan 14, 2008 at 22:41
Baldman

I have an auto locker in the front of my Hilux and the stock limited slip in the rear and I could not be happier with the combination. People tell me Toyota LSDs are crap but I am still waiting for the thing to wear out and if it ever does I will fix it because it works very well and I can't see the need for anything else. The locker does not make the steering heavier but it does self centre a little faster. It took me all of about 5 ks in the bush to get used to it and it felt normal from then on. In 2WD on the black top, but with the hubs still locked in, it still fells fine. You can hear a light knocking sound as it unlocks on tighter corners but that is all.

The term "unlocking" on corners is not quite correct because at least one wheel is always driving. It can't return to being an open diff.

The only thing that worries me with air lockers, apart from the cost and the electrical/mechanical complexity of them, is when you engage them you are forcing both wheels to turn at the same speed all the time and no two wheels ever turn at the same speed, not even in a straight line on the freeway. This means one wheel is always skiding and this would have to place an enormous strain on the axle, particularly at the front with the CV joints. You also have the problem of heavier steering and a reluctance to turn sharp corners.

I would be very reluctant to turn it on and would probably leave it too late in many situations. When it was on I would be in a hell of a hurry to get it off again. I have found my auto locker is like a "set and forget" thing. It is there at the precise moment I need it and it is rolling along and not worrying me when I don't.

Brian
AnswerID: 281660

Reply By: Twinkles - Tuesday, Jan 15, 2008 at 08:27

Tuesday, Jan 15, 2008 at 08:27
I also have a Hilux with an auto Lokka in the front and standard in the rear. I fitted manual hubs as well. I fitted the hubs so that I could wind the suspension up and not be running the CV's at highway speeds. I fitted the auto lokka because of price. When driving on dirt roads/tracks that have good traction when in 4wd, then the steering pull back to centre is strong, but on difficult tracks it is not noticable. I took the car up the Burgoyne Gap Track last weekend and it performed fantastic. Very loose large rocks cover the track and roll away under you and further up, where I had the the most difficulty last time because I kept lifting a front wheel and losing forward motion(IFS sucks), I plodded over it. I have also put a softer after market suspension which helps keep all wheels on the ground. If i was going to fit a locker to the back, I would probably fit an ARB or TJM air locker.
Take a look here: http://www.pps.net.au/4wdencounter/articles/difflocks.html
AnswerID: 281701

Reply By: KSV. - Tuesday, Jan 15, 2008 at 10:08

Tuesday, Jan 15, 2008 at 10:08
This topic been beaten to death so many times is not a joke. Appears that there are as many opinions as many people. In my view although manually selected lockers do have some disadvantages (virtually no steering with locked front and don’t like disengage under load) overall they more versatile and practical because driver in control. I find out that rear lockers almost always sufficient to get out of trouble and front need to be engage only in extreme situation and this virtually negate all disadvantages. Plus if doing something fancy one can engage them selectively (say front only) and so on. But IMHO really biggest plus with manual (say ARB) vs auto is the fact that auto-lockers (it is more correct to refer to them as “auto unlockers” because normally they locked and unlocks when turning) send all torque to wheel with most traction leaving “non-traction” wheel without any torque at all. While this is perfect in very uneven rocky terrain with one wheel of the ground, I still do not believe that this is best way to aid traction on mud and sand and similar situation when manual lockers actually sends torque to all wheels.

Cheers
Serg.
AnswerID: 281722

Follow Up By: splits - Tuesday, Jan 15, 2008 at 11:09

Tuesday, Jan 15, 2008 at 11:09
Serg

I think there is a big difference in how these lockers look on paper and how they perform on the road.. It is true they allow the wheel that is being driven faster by road applied torque as it goes around the outside of a corner to overide the locking mechanism and roll ahead of the driving wheel on the inside but if that situation changes, e.g the inside wheel losing traction or riding up over or down through an obstacle so its speed suddenly equals that of the other one, the diff will lock again in the blink of an eye. This "locking" or "unlocking" will alternate from side to side in a fraction of a second depending on the terrain but the end result is as long as at least one wheel at the front can maintain its grip on the road, the rear axle is getting enormous assistance.

I found prior to fitting the Lokka it was common to have one front wheel loose traction on steep hills and take the whole open front axle out of the action. The rear would then have to do all the work. Sometimes it did but one wheel would often start to spin. The limited slip would then come in and usually fixed the problem but occassionally I would end up with both rear wheels and one front spinning and the car going nowhere.

Since fitting the Lokka that has not happened and I have yet to find a rough spot that I can't get through. It will happen one day though, probably in mud or sand, and I will be sitting there with all four wheels spinning but in a situation like that, even air lockers at each end would not make any difference.

Brian
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Follow Up By: KSV. - Tuesday, Jan 15, 2008 at 11:52

Tuesday, Jan 15, 2008 at 11:52
Brian,

I have not said that autolockers not working – they do indeed. Furthermore, there *ARE* some (IMHO minor) situation when autolockers seems to be better. Both system got proc and conc. But I still believe that overall manual control is more versatile. As least it is suit my driving habits very well.

Chers
Serg.
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FollowupID: 546064

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