Originally posted by David K
A-TRAC when on, matches tire rotation across the axle, same as a locked differential.
Only difference, a locking differential does not control wheelspin like A-TRAC. I prefer having a locking differential on-demand, and a limited slip
unit in both differentials 100% of the time.
Had my Rubicon only been equipped with A-TRAC, I would not be attempting this tricky hillclimb.
Originally posted by Baja12valve
I watch these videos and I see that A-Trac is just another name for a limited slip. If I lift 3 wheels of my truck and rest the axles on large
platforms of wood, not just some post, but a platform, my remaining wheel will burn rubber on the pavement, pulling the truck off. If I lay into it on
pavement, I leave 2 rubber marks, if 4wd, I leave 4 rubber marks. If I have one wheel on sand, one on pavement, both will get power. What is the
difference?
Limited slip is just that limits the amount of slip, but is not 100%. A-TRAC is nearly non-slip... Lockers are 100% true, but A-TRAC is the next best
thing... it is what Toyota has (at no extra charge for the Off Road models).
Limited slip is also controlled by the clutch arrangement. You can be aggressive or not there can be a huge difference. If I can get one (if the rest
of the truck is on blocks) two or all four to burn rubber on pavement, sort of hard to beat that, except with lockers. When I see the A-trac video
with the truck on rollers, I know I can do the same thing. Same same.
Originally posted by 4x4abc
just curious - could any of you describe the difference between limited slip and A-Trac?
A-TRAC matches tire rotation across the axle... Limited Slip slows the spin of the non-traction tire so SOME of the power normally lost is shared with
the traction tire.
A reason A-TRAC isn't the same as lockers is that there is a momentary release or slight slip which is what allows it permit unrestricted steering
control and also ensures the brakes are not needlessly applied. So, yes A-TRAC is a limited slip... but one on steroids and is used when other
vehicles would use lockers while in low range. Otherwise, in high range, the truck uses TRAC limited slip and really improves the ability over my pre
TRAC '05 Tacoma with only open differentials.
The A-TRAC system needs a hydraulic brake booster but the TRAC limited slip system works off the standard vacuum break booster. Only the Off Road TRDs
with A-TRAC have the hydraulic booster, all other Toyotas use a vacuum booster.
Originally posted by Baja12valve
Limited slip is also controlled by the clutch arrangement. You can be aggressive or not there can be a huge difference. If I can get one (if the rest
of the truck is on blocks) two or all four to burn rubber on pavement, sort of hard to beat that, except with lockers. When I see the A-trac video
with the truck on rollers, I know I can do the same thing. Same same.
It would be interesting to see limited slip tires on three rollers and one tire on the ground, blocked. I know the A-TRAC can pull my truck over any
problem the body will clear... and am not so sure that TRAC will, but maybe?
Ken, you do understand that the Hawaiian video you posted showing the Rubicons and FJ Cruiser with its front tire in the air, spinning, did not have
A-TRAC.... or it wasn't turned on, if it did have it... It also didn't appear to even have TRAC on (limited slip)... Like my 2005 Tacoma in low range,
there was no traction control on the front tires.
Ken, the A-TRAC hack is for Tacomas that DON'T have A-TRAC... What the 'hack' or '4-low trac mod' does is fool the computer into thinking the vehicle
is in high range when it is in low range.
All (late model) Toyotas have TRAC (limited slip) in H2 and H4, but no traction control in L4 (unless you get the Off Road package... and then you get
an even stronger system, A-TRAC).
So, for the non-Off Road 4WDs, they do the 4-low trac mod (you cut a yellow wire or put a switch in it) and it makes the limited slip work in low
range and that greatly improves traction. We with the Off Road package have A-TRAC which is better than TRAC and pretty much as good as lockers front
and rear... Only Toyotas with a hydraulic brake booster can have A-TRAC, so for the others, TRAC is all they can get, but it is still better than just
having open differentials in low range.
I don't know why Toyota doesn't just make TRAC work in L4, but maybe it is an incentive to buy the Off Road package so one can have A-TRAC and a rear
locker?
"If I owned a Toyota, you bet I would "Hack" my A-Trac in order to use it in low-speed situations." Ken, A-TRAC works in low speed situations, and
only in low range... If I can drive faster than 20 mph, I am not in low range. In fact, because TRAC works so well in high range, I rarely need low
range... but when I do, it is an awesome experience with the A-TRAC!
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