Limited Slip Faceoff: Detroit TrueTrac vs. ARB Air Locker

[drodio]

Wow guys, all of this feedback is super helpful. I hadn't considered prioritizing the winch over the lockers... mainly because I've already been in situations where I wished I had some level of locking diffs, but I haven't yet gotten myself into a situation where I've needed a winch. But that's definitely something to think about.

After all of the back & forth above, I've now started to lean towards an ARB locker on the rear that I can turn on & off, and nothing on the front (maybe a winch for extreme situations)... whereas before I was leaning towards a true-trac. I'd love to hear from more people who have had a TrueTrac specifically, if there are more of you out there.

As always, thanks a ton for all of your feedback & guidance; much appreciated.

 

[bjm206]

I have run both the ARB selectable locker (front and rear) and the TruTrac (front and rear).

The selectable locker is the ultimate in traction. Turning will be harder with the rear diff locked and sometimes impossible with the front diff locked. On slippery highly cambered roads the axle will tend to slide down the camber (off the road) with the locker engaged. Typically you will use the selectable to get through a difficult section then unlock until you need it again.

The TrueTrac (torsen) is a distant second place as far as traction goes. You will need the brakes to torque transfer anytime one side of the axle has little or no traction. Under most conditions the TrueTrac will not effect handling when engaged and it does not have nearly the same issues on slippery cambered roads.

As you probably know the speed based limited slips should not be used in the front diff as they will greatly effect steering when engaged.

Which diff works best depends on what problems you are having or which ones you are likely to see. Rocks are the domain of the selectable. Strait sections of mud and sand are best tackled with the selectable but the torsen (TrueTrac) will also usually work ok. Long sections of slippery cambered surfaces seem best suited to the torsen (TrueTrac).

 

[Bergum]

Lockers and Arb's are for getting you into problems.
Winch is for getting out again...

B4x4.no

 

[DaJudge]

I have been running a True-Trac in my front axle for 6 years. It has performed flawlessly on every surface, including smooth wet granite. The only thing I can say about it is it is picky about the fluid. I change mine once a year (more if I have taken a lot of trips) which is 8,000 to 10,000 miles, and that seems to be enough. I chose it because of price and maintenance ( no air lines to worry about, no compressor, etc.). However, for the rear of a truck I would recommend a selectable locker. I had a Ranger with a Torsen style LS in it and it was down right dangerous in slick conditions. I had to drive with a very light foot.

If you can afford it go with the ARB in the rear. The True-Trac in the front would be fine.

 

[Buliwyf]

My F250, while capable, needs to make some tight turns in 2wd. Even in slippery, gooey offroad conditions, I have to shift out of 4wd to make some manuevers whithout the truck hopping and jumping. Even when snow wheeling. 3 point turns are normal for big trucks. I'm constantly shifting the floor shifter in and out of 4x4. I allmost allways try turns in 2wd first.

Often I need more than a LS or open diff during those moments. And a ARB that's locked up would be a pain. An ARB that's open would be useless. Tight turning on a grippy but steep grassy/sandy uphill really shows the advantages of the Detroit. But it takes a while to learn to get the most out of that diff.

So I run a Detroit locker in the rear and a open diff up front.

IME on a truck as big and heavy as the F350, a rear Truetrac is not optimal. Wouldn't be much better than the stock limited slip if it was shimmed correctly (cram as many shims in as possible) and use zero friction modifier. Truetracs are the cats meow in a light wheeling Nissan Titan.

If you drive it carefully it's fine. You have to drive responsible in snow and run AT tires in the winter, but we allready do that anyway right? A Superduty with a Detroit rear and a Truetrac front will go anywhere a Superduty should. If you put anything up front, make sure it's a Trutrac, Limited Slip, or selectable. Don't put a autolocker or spool up front. Some folks have run the Detroit up front, but generally they are the types who only are in 4wd on a muddy farm road traveling in a straight line. Since I'm rarely in 4wd, I'm considering a Detroit also in my front diff, but for now, I need to spend money elsewhere instead. I rarely spin a front tire, so far the truck is a beast with just the locker in the rear.

Lockers aren't just for hardcore wheeling, they have many practical uses. My Detroit gets used every weekend and I miss it when I'm in a truck without it. My F250 has never needed a winch, I don't hardcore wheel with a truck, thats what dirtbikes like the Kawa KLR and Honda CFR450r are for.

Besides, you have that awesome Visteon/Sterling 10.25/10.5" rear axle, it can handle anything a Detroit is going to throw at it with ease. Keep in mind that in a big, long, heavy truck, with insane strong axles, the quirks of a Detroit are hardly noticable and easy to work around. That diff was born for big trucks. It might be a nightmare in a Jeep or Toyota though. I'm also assuming you have a auto transmission. Slushboxes are much smoother, Detoits hate manuals transmissions combined with daily driving.

Truetracs are great in the front of a Superduty because it's rare for a Superduty to lift a front tire. Trutracs are useless with one wheel in the air. My F250 lifts the rear tires more often, and Truetracs, even with the E brake on don't really work well enough in the big heavy trucks.

 

[drodio]

@Buliwyf, so just to get terminology straight:

You're saying you run a Detroit locker in the rear. How would that be different from an ARB locker in the rear? Same thing (basically) isn't it? They both fully lock the axle? Is there a meaningful difference between Detroit lockers & ARB lockers from a functionality perspective?

And when you write "A Superduty with a Detroit rear and a Truetrac front" I assume you mean a Detroit locker in the rear, and a Detroit TrueTrac in the front, right?

 

[Buliwyf]

Yeah Detroit locker rear. Detroit Truetrac front. A Superduty like that would be nearly unstoppable for anywhere a superduty has any practical right going.

The ARB is open, or locked solid. Controleed by a switch on the dash.

The Detroit is allways locked while driving straight. But when you enter a turn the faster spinning outside wheel can automaticly ratchet free. When you apply alot of throttle that ratcheting may not occur, friction holds the dif locked, and stomping on the gas while turning will spin the inside tire, lock the diff, then spin both tires and send you spinning out of control. Some prudence and self control is required in snow and ice.

Nascar runs Detroit lockers. So do a few of us with Mustangs. Allthough I still prefer a extremely tightly shimmed stock LSD diff in my '04 Mach1.

So sometimes the Detroit is much easier to turn off road than a locked or unlocked ARB. And the Detroit can be handly to reduce wheelspin hauling loads in 2wd up gravel roads or sandy dry pavement where you wouldn't normally engage the ARB or 4wd.

Basicly the detroit is very much like two Craftsman ratchets taped side by side together by the handles. The sockets are your tires, the handles are you power input form the driveshaft. If one of the sockets starts spinning faster than you turn the handles, then that side starts to ratchet free. Eaton has a nice Youtube vid on how the Detroit works.

Every once in a while it'll also windup and unlock bang in a parking lot. Sounds like your axle expoded. Usually it just clicks though.

 

[drodio]

OK I think I understand -- so the Detroit locker has no air compressor involved. It's a passive system that's based on relative wheel spin ratios and amount of throttle applied?

Man, the idea of it unlocking in a parking lot freaks me out.

At first blush, I'm inclined to stick w/ the options of either ARB fully locked or TrueTrac helical gear, but I'll look into the Detroit locker, and I appreciate the additional option to explore.

 

[Buliwyf]

ARB rear, and Trutrac front is also a very, very good setup. This would be the setup I'd get if I didn't have such specific needs to haul trailers offroad and back them up into tight offroad spots.

Yeah the Detroit Locker has no airlines or electronics. It's locked 24/7 and unlocks one wheel for turns if you are gentle on the gas. It requires gentle throttle in snow/rain and makes some noise. It's a hairy chested diff with some attitude. Not for everyone.

It's just another diff you should add to you homework list. You got some reading to do.

Avoid:
-The cheap auto lockers. Aussie, and Lockright don't unlock easy enough in fullsize trucks and are messy to drive.
-Crappy E lockers. Pretty sure nobody makes a decent E locker for either of your axles. Especially your front Dana 60. That E Locker was a complete flop.
-combining snow, ice, Detroit locker, mud tires. Use AT's in the winter.

I'd really like to try an Ox Locker up front. But that's serious $$$$.

 

[General Automag]

Unless you're rock crawling, I can't see the need for locking differentials. The ARBs are nice, but they are more than double the cost of a good locker or limited slip differential. Everyone that I know of that has ARB air lockers installed has had leaks in them, later if not sooner.

For what it's worth, we have Auburn limited slip differentials in the front and rear of our Land Cruiser, and our full size truck was ordered with a factory limited slip differential in the rear. So on the truck, we really have a 3-wheel drive considering the stock 4WD IFS setup in the front. Are you hooked on your brand because there are a lot of options out there? We considered locking differentials, but we occasionally have ice and snow, and I don't like the way most lockers behave in turns and when on slippery surfaces. We couldn't be more happier with the LSDs.

If you do happen to get stuck, then use your winch. Actually, we bought winches for the vehicles before anything else which still makes a lot of sense.

 

[Buliwyf]

LSD's might be ok for a Landcruiser, but they aren't going to do jack in the rear of a fullsize Ford. Even shimmed to the max if a wheel is airborne you're done. And my big truck spends too much time in 2wd turning. Without a rear Detroit locker I'm in bad shape at each of my favorite offroad hiding (parking) spots where I unload my dirtbike.

Situations where I have enough grip to wind my drivetrain up while turning offroad are still slick enough to spin my rear tires. Spinning a rear tire while climbing gravel, or sharp rocks lock in ice, is a quick way to tear my tires open 10 miles offroad.

Lockers aren't just for rock crawling. Were they even invented for offroading toys anyway? Heavy Dump trucks and Semis have Detroit Lockers for a reason, and it ain't for play time.

And the OP deosn't have many quality choices for that truck.

Rear Sterling/Visteon 10.25/10.5" axle only has these choices:
-Detroit Locker
-ARB Locker
-Detroit Truetrac (lame in the rear of a Superduty)
-Yukon Locker
-Factory LSD shimmed prybar tight (as lame as the Truetrac)
-open

Everything else for that axle is crap.

Front Dana 60:
-Open (my recommendation, especially if you have snow and a Detroit locker in the rear)
-Detroit Truetrac (also good up front)
-Ox Locker (oh heck yeah!)
-ARB Locker

Front Dana 50:
-Open
-ARB

 

[4x4junkie]

Everyone that I know of that has ARB air lockers installed has had leaks in them, later if not sooner.

4 ARBs in two vehicles going back to 1997. Leaks are something I've never once had an issue with (seems like that should be enough time if a problem was to develop). A friend has had his since 2003, again no leak problems.
Seems whoever is installing them for your friends or whoever is not being careful with things like the seal housings or attaching the bulkhead fittings to be having a 100% failure rate like you mention.

 

[Mr. Leary]

I have had a truck that was locked on both ends, and one that is locked in the rear with a detroit tru trac in the front. I have been much happier with the later. Here is why. Front locked can be kinda scary... you are usually going up something gnarly if you need to lock it, you usually have to make turns, and sometimes you need to re-adjust your line in reverse. Turns and in reverse are not nice on your equipment with the front fully locked, and with a truck as long as an F250, you will need to make turns, no question about it. Good news is that your wheelbase will aid you in climbs. The tru trac is not a full locker, but it will give you a boost in traction, and you can get good at "helping" it to act more like a full locker with some practice.

I doubt that you will find yourself in many situations where turning is less important than optimal traction. There is no problem putting a tru trac in a front diff, people do it every day. selectable locker in the rear, and your mods are still completely transparent in 2wd.

 

[mogwildRW1]

Another video for your collection

 

[leelikesbikes]

i have run full detroits, ox lockers, arb's, and now a trutrac front selectable rear. my last rig had arb's front and rear and i really got sick of chasing air leaks and dealing with compressor problems, i do alot of snow wheeling and the arb's always seemed to be more problematic in cold temps, and when your in deep snow and both of you lockers go out it sucks. my rig i have now has had the lockers and gears in it for a couple months now and i just got back from a trip to montana on some reallt slick roads, overall i am very impressed with the tru-trac front, it is seamless and you dont even know its there until you need it. in the rear im running the aam factory powerwagon locker that is a gear driven limited slip/full locker, electronically actuated. the limited slips are fine on the icy roads.