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David K
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| Quote: | Originally posted by Fernweh
Part of this whole equation, regardless of all the fine vehicles with their nice equipment, is definitely the skill level of the driver.
As Harald had mentioned before all the fancy electronic ESP, A-track and other computerized "4x4" systems - are reactive ones. The traction control
system has to first encounter some adverse conditions, before it will react.
The driver controlled differential locks are proactive traction devices. The (hopefully) skilled driver has to read the trail and he has to make the
decision when to use the diff locks and which ones - before the vehicle gets into "trouble".
Karl
[Edited on 3-31-2012 by Fernweh] |
Agree... and the best way to descibe A-TRAC is it is like having 'automatic lockers on all 4 tires. You have open differentials, so steering is never
a problem or chirping on hard ground (granite or asphalt), but as soon as any tire(s) loose traction, the A-TRAC goes to work and applies the amount
of brake force to the spinning tire to match it with the traction tire... then they both rotate at the same rate as you move forward.
So, it is far superior to limited slip differentials or standard traction controls which in both cases have a limited amount of force and thus can
only slow down the spin speed of the loose tire and not match it with the traction tire... which may not be enough to move you ahead.
A-TRAC is not as 100% as front and rear lockers, because (as you said) it is a reactive system and doesn't go to work until you need it... so some
spin will happen first. Lockers keep you crawling ahead without any brief spin of any tire.
The Tacoma Off Road 4WD does also have a rear locker, and you can have it and A-TRAC on at the same time... so if your forward speed ever comes to a
stop or nearly a stop (under 3 mph), the A-TRAC reacts on the front tires to find traction.
[Edited on 4-15-2012 by David K]
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Fernweh
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DavidK,
we should ask Harald (4x4abc) what he would call a true full time, all-wheel 4x4 drive truck which has both traction control systems.
The computerized ESP and the mechanical differential lockers, not only on the front and rear axle, but also a diff locker in the center - the transfer
case.
Would be interesting to hear his view on it
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David K
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I would bet he would agree that manual hubs beat an ADD (or auto. locking hubs), and lockers beat any traction control system.
So far, and after three Tacomas with an ADD (automatic disconnecting differential), no problems with the shift-on-the-fly 4WD.
All 3 of my Tacomas had the rear locker, and while it sometimes takes a couple of tries to lock it, they all have worked. My current Tacoma with all
the electronic traction controls has actually been the best off roader of them all, and I attribute that to the traction controls. So far, after 2.5
years and 36,000 miles, not one problem with it. Which is what keeps me in a Toyota, it is just so impressive how well they are built and how good
their four wheel drive works!
[Edited on 4-15-2012 by David K]
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Ken Cooke
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| Quote: | Originally posted by David K
All 3 of my Tacomas had the rear locker, and while it sometimes takes a couple of tries to lock it, they all have worked.
Which is what keeps me in a Toyota, it is just so impressive how well they are built and how good their four wheel drive works!
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My Rubicon only requires that I touch an on-off switch, and it locks (rear and/or front) instantly. Why doesn't your Toyota 4WD system have that
ability? This is probably why an intermediate system like A-Trac was utilized, when your lockers cannot/will not activate.
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Barry A.
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My Nissan X-Terra has an electric rear locker------it often is tricky to get it to engage---- or disengage for that matter. Gets a little frustrating
at times, but eventually it does lock and unlock. Strange!!!! No "locking" or "unlocking" on the fly, or at least it never will for me unless I am
lucky.
Barry
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David K
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Barry and Ken... let's not confuse the Transfer Case (going into and out of 4WD) with locking differentials or A-TRAC, or any traction controls
(limited slip)...
In a Tacoma: Going into H4 or back to H2 can be done moving (up to 60 mph) or stopped (sometimes a few feet of movement from stopped to fully engage
or disengage)... This is because it (and your rigs I believe) have an ADD (automatic disconnecting differential).
Going from H4 (High Range 4WD) to L4 (Low Range) and back to H4 or H2 is done while stopped, in Neutral.
The traction control (called TRAC by Toyota) is automatic and on in H4, unless I deactivate it by pressing a button. The A-TRAC is on in L4, unless I
deactivate it by pressing a button... easy. To deactivate either is to allow open differentials and tire spinning if desired. I find four wheeling in
High Range with TRAC on and in Low Range with A-TRAC on much more impressive.
The rear locking differential is activated by pressing a button while stopped in L4, and sometimes takes a few feet of rolling to engage and disengage
(the gear teeth need to line up for the locking key to insert).
The A-TRAC has taken me to Santa Maria and beyond without ever using the locker, and that was impressive... You did see how rough the Widowmaker was
and how deep the bog was in the video clips, right?
I also used A-TRAC when I was climbing a hill and dropped into ruts so that both back tires were in the air... A-TRAC pulled my truck out. I turned
the TRAC off in H4, on the beach in Baja, with tires at street pressure and burried it. I then went into L4 with the A-TRAC and the truck climbed out
of the stuck without me getting out to clear away the sand first.
So, Ken... without pushing any buttons and just going into L4 on the transfer case selector, I have pretty near the same traction abilities as the
Jeep Rubicon with front and rear electric lockers, but I don't have to turn off A-TRAC to make a tight turn, which with lockers... specially front
lockers is less than easy.
I will agree that lockers are perhaps smoother, no lag or slip, and work great for the extreme. A-TRAC can seem jerky, allow some slipping before
activating and makes noise when it is working... but it cost me nothing extra, and I am happy about that.
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rts551
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It cost you when you bought, whoops, leased the truck.... try the rock climbing trail and let us know how ou did.
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David K
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It did fine, thanks... Yes, I always get an Off Road TRD 4WD Tacoma... primarily because that comes with a locking differential... the added bonus was
the addition of A-TRAC in the Off Road Tacomas starting in 2009 (it has been in Land Cruisers, FJ Cruisers, other Toyotas and Lexus SUVs for many
years).
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4x4abc
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slow down guys - you are all over the place
sounds like 10 year olds taking about sex - lotsa enthusiasm, very little knowledge
the me start with lockable wheel hubs
wheel hubs have nothing to do with traction management or lockers - they simply connect or disconnect the wheels (can be front or rear) from the axle
shafts - the same shafts that bring torque and rotation from the differential to the left and right:
http://4x4abc.com/4WD101/hubs.html
Harald Pietschmann
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Ken Cooke
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| Quote: | Originally posted by David K
The rear locking differential is activated by pressing a button while stopped in L4, and sometimes takes a few feet of rolling to engage and disengage
(the gear teeth need to line up for the locking key to insert).
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You have to completely stop your vehicle to activate your locking differentials? 
My Rubicon package cost an additional $4,000.00 - A little pricey, but a bargain that included;
Front/Rear Limited Slip Differentials (Full Time)
Front/Rear Mechanical Tru-Lok Locking Differentials (On-Demand)
Heavy Duty Rock-Trac "Super Low" 4:1 Transfer Case gearing
Fixed Yoke (not Slip Yoke)
Rocker Guards
Dana 44 (center section) axles
All the good stuff!
For a mid-sized pickup truck, your TRD Tacoma is also a great package. It can be a challenge to move the lever-activated transfer case into position,
but there are after market products that address this problem.
In 2003, I knew that I wanted a package that featured the above features included in one price from the factory - since I didn't have the extra $$ for
modifications after losing so much money after modifying my Ford Ranger to perform like a Jeep. Yeah, right. 
I knew that had I purchased a Tacoma, a straight-axle conversion (w/coil overs) would be at the top of my list for modifications. A bit pricey, but
it makes the Tacoma unstoppable, able to run a 35" tire. I plan on bolting on a set of 35" tires for my Rubicon sometime this summer.
[Edited on 4-1-2012 by Ken Cooke]
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Ken Cooke
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| Quote: | Originally posted by 4x4abc
slow down guys - you are all over the place
sounds like 10 year olds taking about sex - lotsa enthusiasm, very little knowledge
I have a thread for this: 
Noche Gay (de Travesti) en Tijuana
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4x4abc
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So, Ken, will I see you on the Rubicon with your Rubicon this summer?
You gotta show us what you can actually do with that dream machine
Harald Pietschmann
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David K
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Ken all second generation Tacomas (2005+) have a dial that you rotate to engage the transfer case... for low range you also depress it while turning:
and you have indicator lights for each step...
Interesting that you can actually lock a differential while the gears are spinning?? Must have some kind of syncro in there?
For the Tacoma, you stop and push a button (RR DIFF LOCK):
Then if it doesn't click in, you move a bit and turn wheels a bit... until the light goes from flashing to solid:
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4x4abc
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all diff locks are dog clutches
the will only engage when in the right position, for that there needs to be a difference in wheel rpm left to right
if there is a big difference in wheel rpm (one spinning tire) engaging the diff lock (forcing the two dog clutches together) will destroy the teeth of
the locker
so, to avoid broken parts all manuals recommend to engage the locker(s) when the vehicle is either stationary or if moving, none of the wheels should
have lost traction yet
sensitive drivers with experience can of course (at low engine rpm) still engage the locker(s) when wheel has lost traction. Since the dog clutch
parts will move about 70 times slower (in case of the Rubicon) in low range than the engine rpm, they will engage slowly without causing damage.
Lets say your engine does 1000 rpm, then the wheels will rotate at 14 rpm. Even when slipping, the difference to the non slipping is minimal.
more here:
http://www.4x4abc.com/jeep101/engage-diff-lock.html
http://www.4x4abc.com/jeep101/engage-diff-lock.txt.html
so, if you want to engage you diff lock before getting to an obstacle and you are driving dead straight and the locker teeth are not lined up, the
locker will not engage at all. However, if you would gently steer to one side (and one side only, do not go back and forth) a difference in wheel
speed is achieved and the locker will engage.
Now what to do when you ant to turn the lockers off? Just pushing the button will only remove the force that put the teeth together. If there is an
ever so slightly difference in wheel speed, the teeth are binding and will not disengage.
Here is what I do - I let go of my steering wheel for about 5 seconds. At 1 mph in low range no big deal. The engaged locker forces the vehicle to go
dead straight and without a hand on the steering, no counter force is present - all 4 wheels rotate at the ame rpm and the locker teeth have enough
play to disengage.
nuff rant
[Edited on 4-1-2012 by 4x4abc]
[Edited on 4-1-2012 by 4x4abc]
[Edited on 4-1-2012 by 4x4abc]
Harald Pietschmann
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captkw
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axle lock's
btw, this design has been used in outboard gear cases since the late 50's..fact for the day.........K&T
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durrelllrobert
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Splain This about TRACTION CONTROL
My GMC Yukon has a traction control system with an on-off switch on the dash. If I shut it off on a long raod trip (ie: Ensenada to Phoenix) I get an
extra mile per gallon even though the highway is relatively straight most of the way. I have made this trip with the switch in both the on and off
positions to verify this result. 18 mpg on/ 19 mpg off
Bob Durrell
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J.P.
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Traction Control ?????????????????
When i was a kid we had two pickups we hauled Hay with one was a Chevrolet stick shift the other was a GMC with a automatic other than the
transmissons they were pretty much the same Truck. The stick shift stayed stuck in the SAND all the time. The automatic rarely ever got stuck.
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David K
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Thank you Harald for the locker info. It agrees with what I experienced with the Tacoma. I guess Ken is lucky he hasn't destroyed his, engaging the
locker while moving at regular speed! Unless there is a mechanism in the Rubicon Jeep that delays engaging until he has nearly stopped moving? With my
locker, I can push the locker button while driving 20 mph, and the light will flash until it actually is engaged (and that happens when I have stopped
or nearly stopped). It also flashes if the button is pushed in H4 or 2WD... but unless you perform the 'locker anytime mod', it only works in Low
Range. The 2WD Off Road PreRunner Tacomas have the rear locker, and it naturally works in 2WD... so with the anytime mod, we fool the ecu into
thinking it is in L4... when it isn't... at least that is what I think I read on Tacoma World?
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4x4abc
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| Quote: | Originally posted by captkw
btw, this design has been used in outboard gear cases since the late 50's..fact for the day.........K&T |
well, dog clutches have been around for a couple of centuries
here is a pretty wild setup at a mine (forgot where and when):
notice how rounded the teeth are from engaging at too high a speed difference
the setup had actually 2 dog clutches - the one on the left was used less often and still has square teeth:
Harald Pietschmann
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Ken Cooke
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| Quote: | Originally posted by 4x4abc
So, Ken, will I see you on the Rubicon with your Rubicon this summer?
You gotta show us what you can actually do with that dream machine |
No, but you will see me with the title to the vehicle - no longer property of Bank of the West.
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