Is ATRAC best avoided?

[Arkansas_SR5]

I've heard multiple accounts on ih8mud of ATRAC possibly overloading the ring and pinion on the 00+ 100 series (see below). This has made me look out for 98-99 examples with the rear locker to avoid the complexity of traction control. How much of a concern is this on the 100 series, as well as other models like the 5th gen 4runner, etc.? Is it better to look for an older model with old-school lockers?

Having said that, maybe ATRAC would be better for some situations, like a slippery shaly hill climb where a locked rig would just spin the wheels?

 

[itsoutside]

I just got an FJ a while ago with ATRAC. I recently got it out to Utah and used it quite a bit without problem. I'll still be installing a front locker asap

 

[Bama_Kiwi]

I have never owned a Toyota or driven anything with ATRAC, but, the SuperSelect system on my Pajero is similar to ATRAC and it works really well.

The key is this sentence, "All had a common theme, they just snapped a tooth due while tires were spinning and grabbing traction on snowed in roads"

This isn't an ATRAC problem, it's a physics problem.

 

[smritte]

The problem people don't seem to realize is things wear out. I spend a bit of time on mud and that school of thought runs rampant. The 100 series is an AWD vehicle that's 20+ years old. AWD causes way more wear on a front diff then a rear.
I'm not sure how the ATrac system caused a ring gear to break though. Its a traction control system that applies the brake to try to slow a spinning axle. Traction control systems that operate like this work "OK" but are not fallible. Things like letting off the throttle to help it is usually a good idea.

I agree with @Bama_Kiwi. Its a physics issue.

20 plus years on a ball joint is pretty good for one that sees off road. A "creaking" ball joint was worn out a long time ago.
I have no sympathy for anyone that doesn't check things but waits until it breaks then complains. If I break something with "Normal usage" I step up and replace the offending part with something stronger. If its not available, I chose the wrong vehicle to build.

People tend to think that Toyota's are indestructible. Their very well built and some parts are built a bit stronger then necessary. One must look carefully at the size of the axles on whatever vehicle they want to off-road.
The 100 series has an 8 inch ring gear in the front. A Dana 44 is 8.5. If I didn't build the crap out of the Dana 44's in my other vehicles, 35's would are really pushing their strength with lower gears. The dana 44 is a solid axle and way stronger then the 8 inch independent in the 100 series or the Tacoma's. What that means is, if your going to be hard on it, you need to step up and build it properly.

 

[AggieOE]

The problem people don't seem to realize is things wear out. I spend a bit of time on mud and that school of thought runs rampant. The 100 series is an AWD vehicle that's 20+ years old. AWD causes way more wear on a front diff then a rear.
I'm not sure how the ATrac system caused a ring gear to break though. Its a traction control system that applies the brake to try to slow a spinning axle. Traction control systems that operate like this work "OK" but are not fallible. Things like letting off the throttle to help it is usually a good idea.

I agree with @Bama_Kiwi. Its a physics issue.

20 plus years on a ball joint is pretty good for one that sees off road. A "creaking" ball joint was worn out a long time ago.
I have no sympathy for anyone that doesn't check things but waits until it breaks then complains. If I break something with "Normal usage" I step up and replace the offending part with something stronger. If its not available, I chose the wrong vehicle to build.

People tend to think that Toyota's are indestructible. Their very well built and some parts are built a bit stronger then necessary. One must look carefully at the size of the axles on whatever vehicle they want to off-road.
The 100 series has an 8 inch ring gear in the front. A Dana 44 is 8.5. If I didn't build the crap out of the Dana 44's in my other vehicles, 35's would are really pushing their strength with lower gears. The dana 44 is a solid axle and way stronger then the 8 inch independent in the 100 series or the Tacoma's. What that means is, if your going to be hard on it, you need to step up and build it properly.

Well said. I'm not saying I know everything but the A-Trac doesn't work like a G80 which more-so does just "grab a tooth".

 

[smritte]

A-Trac doesn't work like a G80.

If your referring to the G80 limited slip, you are correct.
An advantage to traction control in a 4wd is it can to a degree, mimic a limited slip without the hard steering you get from having an lsd in the front.
There's some real good systems out there and Toyota has a system using torque vectoring coming out soon. Instead of the brakes slowing a tire, its done inside the diff. Properly done, it could make limited slips obsolete.

The down side of using the brakes to slow an axle is heat and there's only so much you can do.

 

[AggieOE]

If your referring to the G80 limited slip, you are correct.
An advantage to traction control in a 4wd is it can to a degree, mimic a limited slip without the hard steering you get from having an lsd in the front.
There's some real good systems out there and Toyota has a system using torque vectoring coming out soon. Instead of the brakes slowing a tire, its done inside the diff. Properly done, it could make limited slips obsolete.

The down side of using the brakes to slow an axle is heat and there's only so much you can do.

It'd be interesting to be able to manually override a brake-based system. If you know one wheel is up. being able to provide brake control to that wheel like a trailer brake controller could be a more simple software/hardware integration than say a locker. It could function, theoretically, like the Mustang's line-lock system.

 

[KonzaLander]

Atrac is pretty impressive. It works way better than traction assist aids I've experienced in other vehicles. It does require what seems like excessive engine RPM/wheel speed to engage. Excessive wheel spin + traction + 20 year old parts is a recipe for something to break.

Atrac and the front diff of a 100 series is an interesting conversation. In my opinion, a 100 series with Atrac + ARB's would be the most capable configuration. The ARB carrier is much more robust than the factory Toyota 2/4 pinion gear carrier and it would prevent the deflection that causes the common ring gear tooth chewing issue. With ARB's you not only get a stronger differential, but each axle is locked as well. You can search the 100 series section of mud for the advantages/disadvantaged of Atrac vs. triple locked debates.

@Arkansas_SR5 if you are looking for a 100 series, I would not focus or limit my search based on if the vehicle has Atrac or not. I'd focus on finding the best 100 you can based on general care and maintenance, noting if things like side curtain airbags or car seat retainers are important to you, AHC or standard suspension, do the mods you want to do work on the vehicle (example: no LRA tank for 06/07), audio upgrade simplicity (the integrated HVAC/Nav poses challenges), does bronze window tint bother you, etc. That said, I love the simplicity of my 1999 100 with a rear locker.

 

[Arkansas_SR5]

Atrac is pretty impressive. It works way better than traction assist aids I've experienced in other vehicles. It does require what seems like excessive engine RPM/wheel speed to engage. Excessive wheel spin + traction + 20 year old parts is a recipe for something to break.

Atrac and the front diff of a 100 series is an interesting conversation. In my opinion, a 100 series with Atrac + ARB's would be the most capable configuration. The ARB carrier is much more robust than the factory Toyota 2/4 pinion gear carrier and it would prevent the deflection that causes the common ring gear tooth chewing issue. With ARB's you not only get a stronger differential, but each axle is locked as well. You can search the 100 series section of mud for the advantages/disadvantaged of Atrac vs. triple locked debates.

@Arkansas_SR5 if you are looking for a 100 series, I would not focus or limit my search based on if the vehicle has Atrac or not. I'd focus on finding the best 100 you can based on general care and maintenance, noting if things like side curtain airbags or car seat retainers are important to you, AHC or standard suspension, do the mods you want to do work on the vehicle (example: no LRA tank for 06/07), audio upgrade simplicity (the integrated HVAC/Nav poses challenges), does bronze window tint bother you, etc. That said, I love the simplicity of my 1999 100 with a rear locker.

My other concern with a 100 series is its size and weight. we have a lot of tight narrow muddy trails here in Arkansas. My 96 Tacoma performs well here, but I love the ample interior space and generous field of view the 100 offers.

 

[Arkansas_SR5]

The problem people don't seem to realize is things wear out. I spend a bit of time on mud and that school of thought runs rampant. The 100 series is an AWD vehicle that's 20+ years old. AWD causes way more wear on a front diff then a rear.
I'm not sure how the ATrac system caused a ring gear to break though. Its a traction control system that applies the brake to try to slow a spinning axle. Traction control systems that operate like this work "OK" but are not fallible. Things like letting off the throttle to help it is usually a good idea.

I agree with @Bama_Kiwi. Its a physics issue.

20 plus years on a ball joint is pretty good for one that sees off road. A "creaking" ball joint was worn out a long time ago.
I have no sympathy for anyone that doesn't check things but waits until it breaks then complains. If I break something with "Normal usage" I step up and replace the offending part with something stronger. If its not available, I chose the wrong vehicle to build.

People tend to think that Toyota's are indestructible. Their very well built and some parts are built a bit stronger then necessary. One must look carefully at the size of the axles on whatever vehicle they want to off-road.
The 100 series has an 8 inch ring gear in the front. A Dana 44 is 8.5. If I didn't build the crap out of the Dana 44's in my other vehicles, 35's would are really pushing their strength with lower gears. The dana 44 is a solid axle and way stronger then the 8 inch independent in the 100 series or the Tacoma's. What that means is, if your going to be hard on it, you need to step up and build it properly.

The thread is from 2007, when they were still fairly new. I'm not sure exactly how ATRAC would contribute to the failures. FWIW he's a respected Cruiser mechanic who's saying this. He goes on to say the following:

100 Series vs 80 Series

Shotts-you really are too much. You wern't there, yet you wouldn't have backed down. Easy to say. Webwheeling at it's best. I was there, and advised Amando to back down. Had he broken there, (and I believe he would have looking at those front wheels pointing at each otherand hearing the...

forum.ih8mud.com

 

[smritte]

Well. Your call.
The ring and pinion is the same as my 80. My axles are stronger being solid vs independent which makes the diff the weak link. I take things like that I read on MUD with a big grain of salt.

Just for giggles I went into Toyota's data base and found no mention. If it was an issue, I guarantee I would have seen something. If the issue was 2 pinion vs 4 pinion, it wouldn't have been missing teeth on a ring gear.
I have seen very few broken ring gears and the ones I have were either super high milage with a ton of backlash or big tire's with a heavy foot. Normally that snaps axles though.
Then again, never say cant happen.

 

[KonzaLander]

Every year a few guys post on mud about breaking teeth off a ring gear in a 100. Obviously most of these breaks are in vehicles with ATRAC. It's also important to note that most of the 100s sold in the US have ATRAC.

ATRAC in the 100 is quite aggressive. I have never operated another Toyota with ATRAC to know if it works differently on other Toyotas. I could see ATRAC really shock loading a worn diff, especially if a lot of throttle is applied and wheel spin is happening.

Imagine the vehicle is bound up with the driver side tire wedge in rocks while the passenger tire is airborne. With the right combination of wheel spin and throttle ATRAC will do everything in it's power to stop that airborne tire from spinning. All of that torque and momentum will almost instantly be transfered through the diff to the other side.

One thing that simply does not break (or nobody talk about it) are the OEM CV axles in the 100. They are extremely stout and take extreme neglect or extreme builds/situations to break.

My other concern with a 100 series is its size and weight. we have a lot of tight narrow muddy trails here in Arkansas. My 96 Tacoma performs well here, but I love the ample interior space and generous field of view the 100 offers.

The 100 is no mud truck. It's porky and heavy, yet it is way smaller than a modern day full size pickup. I spent 2,500 miles behind the wheel of a new GMC 2500 earlier this year and was never more excited to get back behind the wheel of my 100.

I hope to get down to Arkansas is fall with my 100. I am curious how it will do on the wet narrow trails.

 

[Arkansas_SR5]

Every year a few guys post on mud about breaking teeth off a ring gear in a 100. Obviously most of these breaks are in vehicles with ATRAC. It's also important to note that most of the 100s sold in the US have ATRAC.

ATRAC in the 100 is quite aggressive. I have never operated another Toyota with ATRAC to know if it works differently on other Toyotas. I could see ATRAC really shock loading a worn diff, especially if a lot of throttle is applied and wheel spin is happening.

Imagine the vehicle is bound up with the driver side tire wedge in rocks while the passenger tire is airborne. With the right combination of wheel spin and throttle ATRAC will do everything in it's power to stop that airborne tire from spinning. All of that torque and momentum will almost instantly be transfered through the diff to the other side.

One thing that simply does not break (or nobody talk about it) are the OEM CV axles in the 100. They are extremely stout and take extreme neglect or extreme builds/situations to break.


The 100 is no mud truck. It's porky and heavy, yet it is way smaller than a modern day full size pickup. I spent 2,500 miles behind the wheel of a new GMC 2500 earlier this year and was never more excited to get back behind the wheel of my 100.

I hope to get down to Arkansas is fall with my 100. I am curious how it will do on the wet narrow trails.

Yea the diff seems to be the fuse in the 100 series front ends, and presumably in the 80 series too. Usually OEMs try to make the CVs the weak point.

 

[rgallant]

Traction control takes a different driving mentality. Punching to get past an obstacle is not a good thing, the idea is a more gradual throttle up. I have a brake-based traction control on my 04 LR Discovery and it works well but it took me a while to figure out how to drive to get the best out of it. And I had one Oh Crap moment when I could feel the hit from too much throttle and it was a big hit.

 

[MidOH]

I roasted my front brakes in the mud with this. It works, and is handy. But shame on the manufacturer's for not putting a Torsen style diff in, to work with these systems.