Limited Slip Faceoff: Detroit TrueTrac vs. ARB Air Locker

[nitro-gear]

For most builds dual lockers or even a single locker are not necessary. A quality LSD unit will get you many places, and get you out of trouble as well. If you are going to be lifting wheels, or building a rig that will be used in the "hardcore off road" world, then I would save up for the lockers. They will also allow a talented driver to get through more difficult areas with less tire spin, throttle, and less wear and tear on the axles/ rig in general.

Each rig and build will be unique, and you need to fully weigh what your are building the rig for and where you want it to take you before you decide to purchase a differential. There is tons of good reading and info online, but if you have any questions you can always give us a call.

 

[Happy Joe]

One question that I have had but not seen answered anywhere is; what are the affects on traction controlled and antilock braking of true-track differentials (especially on ice)?
... I'm pretty sure that there would be few issues with weaker/lower torque limited slips like tracklocks.

Enjoy!

 

[Paddy]

I don't know of any way that the traction aids would ever know that there is a true trac in the system. All the electronic systems rely on wheel speeds and if the truetracs keep the wheel speeds more similar than open diffs, then the electronics will just have less work to do in the end.

 

[Happy Joe]

I agree; however, if faced by a slipping/loose limited slip electronic traction systems will, likely, apply a brake to the spinning wheel; which can/could cause a truetrack to perform more like a locker (potentially, not good), on ice.
I suspect that lockers will simply override any electronic traction systems, by keeping all tires spinning at the same rate, when part time 4WD is engaged; as mentioned, sometimes a BIG drawback (slide or screw themselves and the vehicle down hill) on ice.

I have noticed that electronic traction control and antilock brakes can provide much superior control/ braking and hill climbing/descents on ice.

...seem to be talking myself into another set of ARBs, since when disengaged the antilock brakes and traction controls will still work.
..Am I wrong/mistaken?

Enjoy!

 

[Tarrapin Mallard]

I had a thought before reading all of this. I like how this has not helped me at all. My thought was a TT in the back with ARB or OX in the front. I have a 2nd gen. cummins, I use it with a camper on it some times, for pulling heavy trailers other times, and empty some of the time. My thinking is the TT would be good for running most of the time to keep my rear wheels from spinning out on gravel and on gravel roads. The Locker would be for deep snow, sand and other difficult situations. I had a "87 Toyota with TT front and rear and loved them. I could feel it pull a bit on the front, but not bad. My question for anyone that has run this setup in this type of rig is. How does it act empty and on ice or snow? In Oregon we do not salt our roads and where I live we can have ice on the side roads for months. Also I travel over the mt.s quite a bit and don't want to loose my ability to go faster than I should over the pass because of wanting a bit more traction when empty running around town.

 

[CBE]

I have a Detroit TrueTrac that came as original equipment in my rear axle (a Dana S135). I've never had to lock the hubs in 16 years. I've used the 4WD transfer case quite often, especially in 4LO, but never bothered to get out and lock the front (manual hubs) because the TrueTrac has always been enough to keep going. If a TrueTrac is durable enough for a 13,500 lb rated axle with a 14.24" ring gear, and a 15,000 lb rated option, then it's probably plenty strong enough for a Dana 60/80/110/130, and the 11+" ring gears in Rams and GMs. I retired a Quadravan with a Dana70HD rear that had Powr-Lok, and sold an F-250 with a Dana 60 rear and a Trac-Lok, and the effectiveness of the Detroit TrueTrac beat the other limited slip systems hands down.

 

[Buliwyf]

I had a thought before reading all of this. I like how this has not helped me at all. My thought was a TT in the back with ARB or OX in the front. I have a 2nd gen. cummins, I use it with a camper on it some times, for pulling heavy trailers other times, and empty some of the time. My thinking is the TT would be good for running most of the time to keep my rear wheels from spinning out on gravel and on gravel roads. The Locker would be for deep snow, sand and other difficult situations. I had a "87 Toyota with TT front and rear and loved them. I could feel it pull a bit on the front, but not bad. My question for anyone that has run this setup in this type of rig is. How does it act empty and on ice or snow? In Oregon we do not salt our roads and where I live we can have ice on the side roads for months. Also I travel over the mt.s quite a bit and don't want to loose my ability to go faster than I should over the pass because of wanting a bit more traction when empty running around town.

Trutrac in the rear, and the front locker open, in 4wd, you'll be fine. That's an excellent setup for snow and ice.

The Truetrac can get loose if you have a heavy foot in the snow, but usually it's fine.

 

[Buliwyf]

I agree; however, if faced by a slipping/loose limited slip electronic traction systems will, likely, apply a brake to the spinning wheel; which can/could cause a truetrack to perform more like a locker (potentially, not good), on ice.
I suspect that lockers will simply override any electronic traction systems, by keeping all tires spinning at the same rate, when part time 4WD is engaged; as mentioned, sometimes a BIG drawback (slide or screw themselves and the vehicle down hill) on ice.

I have noticed that electronic traction control and antilock brakes can provide much superior control/ braking and hill climbing/descents on ice.

...seem to be talking myself into another set of ARBs, since when disengaged the antilock brakes and traction controls will still work.
..Am I wrong/mistaken?

Enjoy!

Electronic traction control shouldn't have any issues. I haven't noticed any. Especially the Fords. You're already slipping and sliding around pretty hardcore before the system kicks in.

Now braking in 4wd is a different story. On one hand the truck stops better. There's less chance of locking the rear axle because it's connected to the front, but if you go "full retard" and do something really stupid and lock up all 4 wheels, then ABS might not be able to save you as well as it should. I'd imagine that an auto locker in the axle could compound that somewhat, but haven't witnessed it yet. So I'm careful about stopping distances if I'm on the highway in 4wd. Usually at highway speeds, even with the rear Detroit locker, I'm fine cruising in 2wd on Ohio snow and ice. At low speeds it doesn't matter at all.

There's only one real way to find out. Put in the diffs and find an icey parking lot to see how the truck handles emergency manuevers.

 

[Mundo4x4Casa]

Just a user report on my now front/rear True Tracs. I've had the truck camper out in some pretty deep snow of late (the most we've seen on the west slope, Northern Sierra Nevada for 6 years) and I can report that my expectations on how a Faux Dana 70 and true Dana 80 under a 10,400 pound truck and camper have been met and exceeded. The important difference between say a pair of Trak Locs and these True Tracs is transparency. No slipping at all on icy patches, just a slick transfer of power seamlessly moving to the wheels with the most traction, not the least as in the Trak Locs. No quirks that you must learn to live with. I'm thinking these are the ticket for someone who has a heavy rig and never goes looking to lift a wheel off the ground. For those who haven't seem my latest overbuilt drivetrain tome, here's the link:
http://truckcamperadventure.com/2017/01/extreme-truck-camper-drivetrain-build/
thanks for reading
regards, as always, jefe (Señor doble tracción)

 

[Chorky]

Just a user report on my now front/rear True Tracs. I've had the truck camper out in some pretty deep snow of late (the most we've seen on the west slope, Northern Sierra Nevada for 6 years) and I can report that my expectations on how a Faux Dana 70 and true Dana 80 under a 10,400 pound truck and camper have been met and exceeded. The important difference between say a pair of Trak Locs and these True Tracs is transparency. No slipping at all on icy patches, just a slick transfer of power seamlessly moving to the wheels with the most traction, not the least as in the Trak Locs. No quirks that you must learn to live with. I'm thinking these are the ticket for someone who has a heavy rig and never goes looking to lift a wheel off the ground. For those who haven't seem my latest overbuilt drivetrain tome, here's the link:
http://truckcamperadventure.com/2017/01/extreme-truck-camper-drivetrain-build/
thanks for reading
regards, as always, jefe (Señor doble tracción)

Hey Mundo, not to dig up an old thread, but I'm curious on your thoughts since its been about a year since you've had the TT's on both ends. I'm considering the same for my '97 F350 diesel.

 

[Paddy]

A large majority of criticisms about truetrac are made by people who don't understand the benefits that they offer over a locker, and also don't understand how to maximize the benefits of them. To even compare them to a locker is somewhat unfair to both. It's apples and bananas.
There's a reason why the venerable humvee was gifted with Torsen diffs in both ends, and automatic transmissions. It wasn't because modern kids don't know how to drive stick. They work when needed, and help when not needed. They are transparent, unlike lockers which are a detriment many times.
A clue is that if the truetrac encounters a situation where there is a wheel off the ground, ie zero traction, then they don't become useless, they merely require application of brake. The amount of brake applied is exponential to the amount of traction that will be given. But then when you pop over that obstacle and then need to turn, the truetrac will allow that unlike the locker which will plow straight ahead, off the cliff.

 

[Mundo4x4Casa]

Chorky, the only woe I see with T.T.'s in front is that they want to slightly pull to center even on the highway....unless you have locking hubs, then everything is fine. Our recent trip to the Anza Borrego Desert certainly found the T.T.''s to be invaluable. Your F-350 is a fine candidate for T.T.'s. They are relatively cheap and available for your rig. Paddy, I had wheels off the ground on the above trip and everything just kept churning seemlessly away. A couple vids: You can see the tire lift but not spin:
https://www.dropbox.com/s/xg1lwe92448ry7z/Mogols at great sand hill Anza.m4v?dl=0
For the sand hill I dropped the pressure to 20 pounds; chose 4th gear low range; downshifted to 2nd low range for the moguls. The wide rear wheels helped spread the contact patch into the tall sidewalls a plus since most of the weight going uphill is on the rear axle. Make no mistake this is pure blowsand. That motor cycle was going back down because he could not make it up.
https://www.dropbox.com/s/bfj5y93wsd7vfkw/jefe does sand hill at dry wash of the devil Anza.m4v?dl=0
jefe

 

[Dogmann]

Can you experts tell me which locker would be a good choice for a Suburban 4x2? I know - get a 4x4! But seriously I've seen 4x2's that can do pretty good with some type of locker. So. What would you recommend ?

 

[Dalko43]

Can you experts tell me which locker would be a good choice for a Suburban 4x2? I know - get a 4x4! But seriously I've seen 4x2's that can do pretty good with some type of locker. So. What would you recommend ?

No but seriously, get a 4x4. Putting a locker on a 4x2 is like....putting a locker on a 4x2. If you're going places where you think you'll need a locker, you'll need 4x4 too.

For the original topic: i think Limited slips have their place. They're certainly better than having no traction aids whatsoever. But for even mild offroad/overland travels, a true locking differential is so much better to have. I totally admit that 95% of the time, you will not need one. But for the remaining 5%, you'll be extremely thankful for having one.

 

[ADVdreams]

Honestly this thread should be a sticky. I have been back and forth on this subject for a couple years now, unable to make a decision.

the information discussed here on vehicle weight and tire size is invaluable. The solution for a light big tire’d Jeep is likely not the same for a heavy comparatively small tire’d one ton camper rig.

In particular I had not considered the Detroit locker before, I understand now how this could be easier to live with in a heavier vehicle.

awesome information.