A-Trac Capability Question

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Doug C

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So I've been doing research on a replacement vehicle and noticed that on the Gen4 SR5 4Runners they had an electronic rear locker and on the Gen5 SR5 4Runners they replaced that with A-Trac, but on the Trail version they have both. I'm curious on how capable A-Trac is compared to the e-locker. Any info and help is appreciated. I did a search on A-Trac but didn't find any opinions on it's use or capability. Thanks again.
 

Lindenwood

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4-wheel Atrac is generally going to be nearly as capable as a single rear locker except in big rocks and other slow-crawling situations. Brake-biasing traction control systems require some amount of wheel speed to work, which is not always a great thing when floating tires over higher-traction surfaces due to greater risk of driveline damage and wheel slip.

I have a TRDP and a 3rd gen SR5. I will be putting 2x Truetrac LSDs on my 3rd gen to augment and be augmented by the Atrac. If I could do it all over again, Id have purchased a 5th gen SR5 instead of the TRDP and put in a pair of LSDs in that as well.
 
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Lindenwood

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I was pretty sold on the e-locker when I first decided to get the trail over the SR5, based on my experience with a spooled rear end on my Samurai. However, it didnt take me long to realize I don't think I will ever be doing aggressive 3-wheel boulder crawlinv in my much nicer daily-driven rigs. So, modern traction aids, eventually coupled with stout LSDs (Truetracs as opposed to clutch-type), plus a little left-foot braking, is realistically more than enough to comfortably and safely take me where I need to go.
 
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Winterpeg

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The rear locker is a game changer in very low traction areas like snow and deep sand where you need momentum.

A-trac is awesome when you have traction.... you can climb like a billy goat.

In very tough climbing situations I activate both.

Going through a sketchy mud hole I activate the rear locker and I make sure my a-trac is OFF. You want a bit of wheel spin if needed and you don't want a-trac killing your momentum.
 

Lindenwood

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A quick video where you can see the Atrac doing its thing. Every situation is different, but this should help you at least imagine it a bit better.

Also, in regards to losing momentum in mud, I was under the impression that ATrac minimizes its intervention at larger throttle openings / higher RPMs. Thus, when really getting her some gas to keep the wheels spinning it shouldn't get in your way, right?
 
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IronPercheron

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I have the Sr5 with the atrac.

I also have owned 4 other trucks with lockers, Ox in two, arb in one, and lunch box lokka in the last.

Make that 5... my super duty has a rear e locker that never gets used....

I like atrac better so far. especially on the steering axle... much more control, and smoother operation. No fighting the drivetrain...


That's my .02 friend, safe trails!