truetrac, LSD, ATRAC, TRAC

[shabaka]

ok i searched but came up with nothing....

i completly understand the PROs of an ARB selectable locker
and what it does

i've used the ATRAC system quite effectively on trails with 1 or 2
wheels off the ground

my real question is...
theoreticly or realisticly
should the ATRAC work in conjunction WITH a Truetrac ???
(front or rear)

i noticed the new Sequoia has a "TRAC" system with an LSD in the rear
i just don't have the details of that truck
is that TRAC the same as ATRAC ? ...like a less advanced version of some kind

i know, i know, what everyone will say
"JUST GET AN ARB"
it's not really an LSD vs Locker question/issue
(i think any thinking person knows what Diffs, do what)

i just want to know if the ATRAC would be with or against a Torsen, gear drive, LSD ?

[my034runner]

Just get some ARB's!!! I can get them for you.

I've got my rear ARB in, but am waiting until gears are ready to pull the front and install the gears and front lockers all at once.

But, I've only tried my rear locker a couple of times so far, and I can't really tell you if it's working with or against the a-trac and center diff locker.
Andries and Jason have both their front and rear ARB's w/ gears in, and have both been driving them for some time now, so they would certainly be better equipped to answer what I think your question is.

Did any of that help??

[FJCcrawler]

it should work with it just like in an FJ where you can have the r locker and the atrac work together. .....but if all else fails you always have that ARB option avalible

[bulldog]

Not sure how well the ATRAC will work with LSD and other lockers that work on limiting wheelspin or only kicks in under certain wheelspeed conditions, as the ATRAC also tries to limit wheelspin and might prevent these lockers from actually kicking in.

However with fully selectable lockers like the ARB or elocker it works great. Once you lock the one axle the ATRAC doesn't function on that axle any more as both wheels rotate at the same speed. It does however still work on the axle that is not locked, i.e. if the rear axle is locked ATRAC will still kick in on the front axle. ATRAC doesn't work against a locked axle, but only on the open axle (nothign needed to do for it to work that way). If you lock both axles ATRAC simply stops working all together.

[shabaka]

ok...

i guess the question has nothing to do with lockers

more a question of maximum traction from an LSD

i've read alot and seen in action
applying a little brake to transfer power from an in-air wheel off the ground
to the wheel with traction

this is what the ATRAC does ...to an extent
so if the ATRAC is doing the braking trick for you

will that help create the transfer of power (for an LSD) that the driver would've done manually ???

because the system, ATRAC, has the abillity to act on only one wheel
i.e. the in-air wheel
the two should be a good match, right?

unless i'm missing something huge

[bulldog]

I honestly don't know what will happen. The ATRAC and LSD is esentially doing the same thing and they might ehlp each other or one will never truly work.

Only way to know is to drop an LSD in and test it. I'm not a big fan of LSDs for offroad applications they seem to be of minimal value in the stuff where ATRAC is not sufficient. In actual fact the LSDs I have seen in action were much weaker than ATRAC offroad.

Originally Posted by shabaka

ok...

i guess the question has nothing to do with lockers

more a question of maximum traction from an LSD

i've read alot and seen in action
applying a little brake to transfer power from an in-air wheel off the ground
to the wheel with traction

this is what the ATRAC does ...to an extent
so if the ATRAC is doing the braking trick for you

will that help create the transfer of power (for an LSD) that the driver would've done manually ???

because the system, ATRAC, has the abillity to act on only one wheel
i.e. the in-air wheel
the two should be a good match, right?

unless i'm missing something huge

I know this is an old thread but I just found it... Nissan Titans have ABLS, Nissans' ATRAC. The early Titans easily blow the rear diff (I blew one). Some of the guys used a Trutrac (torsen) style diff as a replacement for the weak stock unit. The lifted, big tire 4wd guys and the 2wd hot rod street guys loved it! From what I read on the Titan forums it was a wonderful combo. It was reported as seamless, hands-off performance that rivaled a locker but was very civilized.

[gaber_771]

i was looking into this option as well today. it seemed like a viable option for those of us who are looking for a little more lock without worrying about the compressor/air line install issues. (Certainly nothing against air lockers, i just don't crawl many rocks and could probably get by here in the Appalachians without 100% lock). Shabaka, try www.justdifferentials.com for pretty good pricing on the lsd unit.

[Photog]

The LSD systems all work in different ways. The Torsen types, that lock up with the applcation of brakes, seems like it would be a good match with the A-TRAC, since the A-TRAC applies brakes to the loose wheel. This seems like it would lock the Torsen diff, and releave the A-TRAC from further work, until it was Torsen un-locked, and slippage was sensed again.

The Torsen can have the torque-bias-ratio (TBR) adjusted. I would guess that a higher TBR would be desired over a lower TBR. Ask the dealer.

Please don't forget to come back and give us an update.

[shabaka]

yeah, after much research,
it is exactly like Brian stated
the LSD/locking action is improved by the A-TRAC and is a seamless match
i have yet to install one because i can't decide on tire size and gear ratios ...and the economy stinks

but it is on my long to do list

and thanks for the link as well

[Lexwoody]

It depends on how tune True-Trac (LSD) is. If not much less than what is a lound (wheel spin) before the system kicks in (Traction Control) , A-Trac/ Trac will take over all the time and wouldn't give the LSD a chance to its thing. Pretty much they do the same thing!

True Trac needs to work before the braking system.

[Photog]

The Truetrac act much like the Torsen, but uses the helical gears in a different way. With both systems, the "loose" tire, still needs to have some traction, otherwise there is no torque to multiply, and send to the tire with traction.

A tire on ice or up in the air, will just spin. This is where A-TRAC is a big help. It clamps down on the loose side, and starts to lock up the diff.

The A-TRAC should make the Truetrac or Torsen act better and smoother than either A-TRAC, Torsen or Truetrac alone. Reducing total wheel spin, reducing wear on the ABS system, reducing trail damage, etc.

I don't think other LSD systems would work so smoothly with the A-TRAC.

[shabaka]

yes brian is correct...
the worm gear, in the truetrac, is always transfering torque referenced by traction/resistance
it is never not "LSDing" (...is that a word??) so it will be seamless in operation

clutch packs will act a bit less smooth, but should work the same in theory

[Photog]

Most "clutch pack" types of LSD require a certain amount of wheel spin, just to engage the clutches. They are not engaged by torque resistance; but mearly the difference in tire rotation between the L & R axles. Unlike the Torsen-type LSD, the clutch-type are not engaged all the time.

That clutch-type has the same effect as the A-TRAC. With the L & R axles turning at similar RPM, there is no engagement of the LSD or A-TRAC. When one side spinns more than the other, the system locks that side down, allowing the torque and power to move to the other axle. These two systems can also be adjusted to be agressive or mellow in their operations, by reprogramming the A-TRAC or changing springs in the clutch pack.

Since the A-TRAC and Clutch-Type LSDs operate so similarly, I believe they would both be trying to engage at the same time, doing the same thing (at opposite ends of that axle shaft).

I believe it would be trouble; but I could be wrong.

[Lexwoody]

Originally Posted by Photog

Most "clutch pack" types of LSD require a certain amount of wheel spin, just to engage the clutches. They are not engaged by torque resistance; but mearly the difference in tire rotation between the L & R axles. Unlike the Torsen-type LSD, the clutch-type are not engaged all the time.

That clutch-type has the same effect as the A-TRAC. With the L & R axles turning at similar RPM, there is no engagement of the LSD or A-TRAC. When one side spinns more than the other, the system locks that side down, allowing the torque and power to move to the other axle. These two systems can also be adjusted to be agressive or mellow in their operations, by reprogramming the A-TRAC or changing springs in the clutch pack.

Since the A-TRAC and Clutch-Type LSDs operate so similarly, I believe they would both be trying to engage at the same time, doing the same thing (at opposite ends of that axle shaft).

I believe it would be trouble; but I could be wrong.

I agree! The new Sequoia has the LSD in the rear and Trac. No A-Trac.

[shabaka]

no, i think you are exactly right
IIRC they also free-wheel off throttle, as when there is little torque input
so i would say that would be one to stay away from

i'm being redundant here but...
i believe the clutch pack diffs are refered to as "speed differential" or speed sensing ...as you said, they do what the A-TRAC does, adjusting for differences in wheel speed
vs the Torsen or "torque sensing" diffs

[shabaka]

well i sheared the R&P on my rear end on my last outing to Holy Cross
so...

i ordered the TrueTrac
i'm still a couple weeks out before i can order the gears
but i'll keep everyone posted, on my results, right here

[Photog]

Any idea what caused the breakage?

[shabaka]

Originally Posted by Photog

Any idea what caused the breakage?

first run with the truck two years ago...
i thought it was a wheel bearing going bad
'cause i've done that several times in past vehicles

once i wrecked it for good on the last trip about a month ago
the "wheel bearing" sound was gone ...brilliant

from what i've researched
it's a combo of the stock carrier and pinion deflecting under load/bind
stronger carriers, ARB,TrueTrac, or Detriot Locker will prevent it
or a solid spacer vs crush sleve will prevent it as well

i'll be doing both

[Photog]

Oh, I remember the solid sleave/spacer issue.

Strong TrueTrac should fix it. You still need a solid sleave/spacer on the pinion, right?

Edit: I re-read your last post. TrueTrac and solid sleave.