Aussie Locker in the front of an AWD vehicle

[spdwaver]

Can somebody please tell me why you should not run an Aussie or a Lock-Right in the front of an AWD vehicle? Then, more specifically, why you can not run one on an FJ80/FZJ80.

Pin_Head asked the question in another thread, and now I am curious to know as well.

I/we are not looking for opinions on the matter, but technical facts as to why it is suggested that you can not, or why you can run one in the front.

Has anyone installed an automatic-style locker in the front of an 80-series Land Cruiser?

 

[toyteg08]

Because all 4 of your wheels take different paths when making a turn. Therefore, they all need to rotate at different speeds. They can't do that if they're locked together. Aussie says their lockers are always locked.

And yes, I read PinHeads's article about how auto lockers work. But if your wheels happen to slip mid-turn, I think that would cause some spooky handling in a LC, or any AWD vehicle with an auto locker in the front for that matter.

Jon

 

[spdwaver]

Here is Aussie's FAQ in regard to general operation and front installations (emphasis by me):

"The “Aussie Locker” design is automatic in that there are no actions required by the driver to actuate the locking capability. The locker is always locked and unlocks in turns when the outside wheel overruns the speed of the inside wheel."

Question: When travelling straight, the wheels are always locked. When turning, do the front wheels experience any differentiation?

"It is possible to install the “Aussie Locker” in the front or rear of all open differential vehicles. It is not possible to install the locker in the front differential of permanent constant 4WD vehicles without installing free wheeling hubs, or otherwise converting the part-time 4WD. Some Jeeps have a part-time 4WD selection, and it is possible to install the locker in the front."

My concern here is with the particular use of "4WD" in that it does not mention "AWD" which is what we have in our 80-Series transfer cases. Our 80-series Land Cruisers are not considered full-time four wheel drive since we do have an open center differential unless locked.

"We "Do Not" recommend the installation of a locker in the front of a vehicle that will be driven on icy highways in 4WD without manual hubs. Driving on any slick surface requires additional attention to handling so test your Aussie Locker equipped vehicle in open areas under adverse weather conditions before driving on roads."

From Powertrax's (Lock-Right) web site:

"Can I install a Powertrax product in the front and rear of my 4 WD?
In most cases where an application is available, the answer is yes. However, we do not recommend installing a unit in the front differential if the vehicle has a full time 4 WD and is primarily used on the pavement."

 

[GXO]

Have you ever driven a 4WD truck with an auto locker in the front?

If that thing happens to catch or pop in a turn at speed you are in for some real fun.

Don't do it. Don't think you are saving money to do it. Save up and do it right.

 

[Impreza]

My concern here is with the particular use of "4WD" in that it does not mention "AWD" which is what we have in our 80-Series transfer cases. Our 80-series Land Cruisers are not considered full-time four wheel drive since we do have an open center differential unless locked.

Full time 4WD (high) = AWD

I'm pretty sure that's the same thing. Correct me if I'm wrong here?

 

[spdwaver]

Have you ever driven a 4WD truck with an auto locker in the front?

If that thing happens to catch or pop in a turn at speed you are in for some real fun.

Don't do it. Don't think you are saving money to do it. Save up and do it right.

Thank you for the reply.

I understand what you are saying, but what I am looking for are the facts as to "why" it will not work. I would not consider doing this to save some money; life is way more important than money. I am only looking for the facts on the subject.

 

[GXO]

The facts are:

- it is not safe
- it is cost effective for a trail rig (not a road driven one)
- there are better solutions, but more costly
- it will cause undue wear on your drivetrain which will end up costing you more in the long run

I have had many many conversations with people over the years on this. I have seen people try it, some people keep it for a period of time on a low road use truck (they drive to/from trails only). In the end, you just need to hit one turn and have it pop, one ice patch and have it lock up and walk you off the road, etc to learn that the above are the facts and you need to be careful.

Good luck.

 

[80t0ylc]

Can somebody please tell me why you should not run an Aussie or a Lock-Right in the front of an AWD vehicle? Then, more specifically, why you can not run one on an FJ80/FZJ80.

Pin_Head asked the question in another thread, and now I am curious to know as well.

I/we are not looking for opinions on the matter, but technical facts as to why it is suggested that you can not, or why you can run one in the front.

Has anyone installed an automatic-style locker in the front of an 80-series Land Cruiser?

Here ya go:

Aussie Lockers:

Read thru these FAQs. The part that is most significant, from the Aussie technical folks, in the
"If only installing one locker should I install in the front or rear?" section:

"If a vehicle has constant 4WD then only a rear installation should be considered."

Also, the section "Can I install in a constant 4WD vehicle" is interesting. But, it's a free country, for now. The decision is yours.

 

[mikgrail3]

Putting an automatic locker in the front of an AWD vehicle renders the AWD functionality useless. AWD is made for on-road high traction surfaces. There is a reason why these trucks have a center differential. It allows all 4 wheels to rotate at different speeds when turning while still applying power to both axles. If you have the front locked with an Aussie or any other automatic locker it will cause the front wheels to bind and lock when turning on high friction surfaces (ie pavement). This is in the FAQ, but it sounds like some here need to read this: Diffs for dummies
Until you have driven with a vehicle locked in the front, it may be difficult for you to understand what takes place. Ever try to lock the center diff on dry pavement? Locking the front will be even worse and may cause a birf to break. Front lockers are for low traction surfaces or for going straight on high traction surfaces (ie climbing a rock or waterfall).

 

[spdwaver]

Putting an automatic locker in the front of an AWD vehicle renders the AWD functionality useless. AWD is made for on-road high traction surfaces. There is a reason why these trucks have a center differential. It allows all 4 wheels to rotate at different speeds when turning while still applying power to both axles. If you have the front locked with an Aussie or any other automatic locker it will cause the front wheels to bind and lock when turning on high friction surfaces (ie pavement). This is in the FAQ, but it sounds like some here need to read this: Diffs for dummies
Until you have driven with a vehicle locked in the front, it may be difficult for you to understand what takes place. Ever try to lock the center diff on dry pavement? Locking the front will be even worse and may cause a birf to break. Front lockers are for low traction surfaces or for going straight on high traction surfaces (ie climbing a rock or waterfall).

I have driven a vehicle with the front diff locked on the street and no, I will not attempt to drive on pavement with the center locked for obvious reasons. I do appreciate information.


I guess I am not making myself perfectly clear that in this particular thread, I am not looking for an excuse to run an auto locker in the front of my 80, nor am I arguing that it should function without difficulty: I am only looking for technical facts surrounding the reason(s) why an auto locker can not function as designed in the front of our 80-series Land Cruisers.

Knowing that this could easily turn into a debate, I would rather have only technical details rather than opinions. It is for this reason that even I am not stating any opinions on the matter or making any guesses.

 

[-Spike-]

Because it can lock in a turn. Or not unlock, if you prefer to look at it that way. Your technicality of AWD is of little relevance. There is torque sent to the front axle. With an auto locker in the rear (which I have experience with) if you put torque to the axle around a turn, the locker is locked and the tires will chirp. If you hold a steady speed in a turn, the diff will ratchet, and not chirp tires. Incidentally, if you go into a turn while engine braking (hard), torque is applied to the diff and the auto locker will lock and chirp the tires.

The technical reason that installing an auto locker in a driven steering axle is not a good idea is that when torque is applied to an auto locker, it locks. Period.

 

[Pin_Head]

My point in the previous thread was that there is no mechanical reason that it wouldn't work, not that it would be a good idea for a truck that is going to be driven mostly on the road at high speeds. Off road, it would perform better in a vehicle with an open center differential in terms of understeer and steering effort than a truck with no center diff. That is because the center differential will split the speed difference between the front and rear wheels. With a locked center differential, there would be a strain on the drive train, understeer and increased steering effort. Even having one autolocker can be dangerous on slipery and icy roads, so having two would be a lot more dangerous.

If by "locking" you mean both wheels turning the same speed as the ring gear, then they don't lock when you apply torque unless you apply enough torque to cause a wheel to slip.
If you go from coast to drive in a turn, they switch which side is locked and driving and which side is ratcheting. Many people incorrectly interpret this as "locking" when torque is applied, when in fact it is side switching due to going from coast to drive. I posted a link to a web site a couple of weeks ago that explains how they work.

 

[Tools R Us]

... Ever try to lock the center diff on dry pavement? Locking the front will be even worse and may cause a birf to break. ...

Driving locked on high traction surfaces isn't recommended, but short term isn't an issue. If a drivetrain part breaks from tooling around on pavement, it's strength was already compromised. The stress loads are much higher when wheeling. I test mine on pavement before most wheeling trips.

...
I guess I am not making myself perfectly clear that in this particular thread, I am not looking for an excuse to run an auto locker in the front of my 80, nor am I arguing that it should function without difficulty: I am only looking for technical facts surrounding the reason(s) why an auto locker can not function as designed in the front of our 80-series Land Cruisers. ...

It will function as designed, this is the problem and why they aren't recommended in steer axles without locking hubs. When locked steering can be bound, tight. The auto locker locks automatically, so can do it without warning, not the best for predictable handling.

The scenario; your cruising, see bus load of nuns in your path, need to throttle and turn, the locker locks, binding the steering and you kill a bunch of nuns, not good.

Selectable or limited slip (pretty much worthless for real wheeling) are the recommended ways to go for the front. I would prefer a spool in the front over an auto locker, that way I would always know what to expect.

 

[lt1fire]

Sean I only know of one guy that has done this. Currently his cruiser is in pieces but i'm sure he will speak up shortly on his real time experiences.

 

[96r50]

The scenario; your cruising, see bus load of nuns in your path, need to throttle and turn, the locker locks, binding the steering and you kill a bunch of nuns, not good.

What is it with these nuns, they always seem to get in the way at just the wrong moment

 

[CreeperSleeper]

Full time 4WD (high) = AWD

I'm pretty sure that's the same thing. Correct me if I'm wrong here?

It's close to the same thing... Close enough for what you are talking about here. What you are failing to see is when you turn, both front tires spin at a different speed. This is not a big deal without a locker. With a locker, physics is trying to make the tires spin at different speeds and the locker is trying to keep them the same speed. This is not much of a problem off road because your tires have the ability to slip in the dirt. On dry pavement, tires don't like to slip. This will cause the truck to keep going straight or the "slip" will occur elsewhere... Like a broken birf, drive flange, inner axle shaft, etc

But you are right, an auto locker will bolt into the front of an 80 and work as designed!

 

[Pin_Head]

What you are failing to see is when you turn, both front tires spin at a different speed. This is not a big deal without a locker. With a locker, physics is trying to make the tires spin at different speeds and the locker is trying to keep them the same speed. This is not much of a problem off road because your tires have the ability to slip in the dirt. On dry pavement, tires don't like to slip. This will cause the truck to keep going straight or the "slip" will occur elsewhere... Like a broken birf, drive flange, inner axle shaft, etc

With automatic lockers, the faster wheel will always be free to ratchet allowing wheel speed differentiation side to side as long as the wheels aren't slipping. The open center differential will take care of the front to rear speed differential, so you won't have understeer, high steering effort or strain on the drive train. The normal operating properties of autolockers would make them considerably more dangerous on a road vehicle, but it shouldn't be a big deal for a trail rig.

 

[treehugger]

Some one is going for the darwin award

 

[KliersLC]

Some one is going for the darwin award

Says the guy with the most flops......

 

[treehugger]

YAP