Limited Slip Faceoff: Detroit TrueTrac vs. ARB Air Locker

The eXpedition

New member
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.
I would like to re-open this discussion here,

I have a 2012 Ford Expedition, is the combination you mentioned is still up to date or did you find something better?

What is the gear ratio of my car ? is it 9.75" or 8.8" ?

What part number is the correct one for me and where to find it?
 

Kottonwood

Adventurer
Well, I see Ford 8.8 28 and 31 spline applications, so I would be covered for the front axle. Disappointingly there is no rear Ford axle applications at this time. In fact, not much is offered because the factory offers an e-locker. However I ended up not getting one in my truck, unfortunately.

I'm probably going to stay away from a selectable locker in the front for the time being.

Right now the plan is to go with a True-Trac for the rear axle.

Then decide with either
  • a matching True-Trac for the front (expensive installation)
  • a lunchbox locker for the front (cheaper)
  • just rely on the factory e-LSD (cheapest).

Honestly it's probably going to be the latter, because money is getting short.

Just wanted to clarify with this one... I figure the poster has figured it out by now anyways, but you can't put a lunchbox in the front 8.8 ifs even though they make one for the 8.8 28 spline. Once the lunchbox is in there is no way to put the snaprings back on the axles to lock them in. Best bet is the truetrac up front... this is what I did.

As for the guy with the expedition.... it shouldn't be hard for you to find out what gears you have.... try googling your vin or something... they probably all came with the same combo that year. Likely 9.75 in the rear and 8.8 ifs in the front. If that is the case the only selectable locker you can get for the rear is the arb. You can put whatever you want in front except the lunchbox as previously stated.
 

Kottonwood

Adventurer
....another note on the lunchbox... the chances of you getting one in without pulling the whole dif are slim to none, has anyone who has ever installed one of these actually pulled that off? They are a very tricky install.... for ease of install I choose the truetrac any day of the week
 

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The eXpedition

New member
Just wanted to clarify with this one... I figure the poster has figured it out by now anyways, but you can't put a lunchbox in the front 8.8 ifs even though they make one for the 8.8 28 spline. Once the lunchbox is in there is no way to put the snaprings back on the axles to lock them in. Best bet is the truetrac up front... this is what I did.

As for the guy with the expedition.... it shouldn't be hard for you to find out what gears you have.... try googling your vin or something... they probably all came with the same combo that year. Likely 9.75 in the rear and 8.8 ifs in the front. If that is the case the only selectable locker you can get for the rear is the arb. You can put whatever you want in front except the lunchbox as previously stated.
Hi,
yes mine appears to be 9.75 rear and 8.8 front.
The only selectable diff lock I found so far is Auburn that works as limited slip when not engaged and fully locked when engaged. But Some people on the F-150 forum says it doesn't work as advertised. They just fail to work.

Any idea about Auburn or did any one once tried them?

Sent from my SM-G900F using Tapatalk
 

Greg5OH

New member
ok so seems half the people are saying a locker in the rear of a manul trans truck is a death sentence on snowy roads, others wouldnt have it any other way.

My truck: 06 F350 chassis, NP205, 37s, dana60/10.5", turbo IDI, ZF5 8000 lbs empty. 172" wheelbase.

Its my daily, and i live in north MI, lot of snow from the lakes. Snow and ice on the highways.
Got a built foxbody with a tight lsd so i know how it is in the rain, likes to be sideways with soem throttle. easy to control if you drive carefully.

Currently the trucks front is open, and a worn LSD in the rear.

I will be getting a true trac in the fornt no doubt. Anything is better than an open diff.
Rear..so do I get the detroit locker, or the true trac?
Lots of highway driving, but also mud, sand, gravel, hardpacked snow, 2+ fluff snow. Basically everything except super deep mud.

What do you recommend? ARB for the rear is VERy expensive, 1200 vs the 700 for a detroit locker.
 

98dango

Expedition Leader
I like arb but there money. I don't like a rachet locker in the rear. The rear of my super duty is limited slip as we'll as front. My ramcharger is spooled in the rear and limited slip front
 

Greg5OH

New member
I like arb but there money. I don't like a rachet locker in the rear. The rear of my super duty is limited slip as we'll as front. My ramcharger is spooled in the rear and limited slip front
would a true trac in the rear be a waste of time for my truclk?
 

oiler

New member
It would not be a waste, but if it were me, given the weight and wheelbase of your truck, I would Detroit it. I have run both, even in the winter and do not mind the Detroit. It is noticeable, but I like the traction. True trac is a nice upgrade, just not a full locker. I have been in situations where I had to apply the brake to get more bias out of it and it was tough with a stick shift. I have a dodge W-350 that is getting a Detroit in back, and a true trac in the front, for me, it's the most usable combo. Selectables are nice, but I really like the simplicity of this set up.

I would tell you to try it and see if it works for you, because that's what matters!
 

1meanz

Mullet Club Chairman
I've got a TrueTrac in my Tahoe with a stick shift. I got it for the good street manners but I flirted with the Detroit Locker and nearly went that way. I haven't regretted one time. The only time I've had a tire off i set the e-brake and it worked great. I was worried about people saying it wasn't a real locker. Well in northern Indiana in the mud, snow, sand that I run in, it ALWAYS works. It's completely undetectable in normal driving but it never lets me down. For the terrain my truck lives in, I'd make the same decision again.
 

Buliwyf

Viking with a Hammer
ok so seems half the people are saying a locker in the rear of a manul trans truck is a death sentence on snowy roads, others wouldnt have it any other way.

My truck: 06 F350 chassis, NP205, 37s, dana60/10.5", turbo IDI, ZF5 8000 lbs empty. 172" wheelbase.

Its my daily, and i live in north MI, lot of snow from the lakes. Snow and ice on the highways.
Got a built foxbody with a tight lsd so i know how it is in the rain, likes to be sideways with soem throttle. easy to control if you drive carefully.

Currently the trucks front is open, and a worn LSD in the rear.

I will be getting a true trac in the fornt no doubt. Anything is better than an open diff.
Rear..so do I get the detroit locker, or the true trac?
Lots of highway driving, but also mud, sand, gravel, hardpacked snow, 2+ fluff snow. Basically everything except super deep mud.

What do you recommend? ARB for the rear is VERy expensive, 1200 vs the 700 for a detroit locker.
I'd recommend sticking to your plan, one step at a time unless you plan on re-gearing.

Put the Trutrac in the front, but just rebuild your rear LSD and shim it tight. Not a whole lot of hardcore climbing in Mi last time I checked. If you feel like you need more, then try the Detroit in the rear. You might be good with just that Trutrac and a really tight LSD. Great budget setup possibly? Use no friction modifier. A complete set of mudrated chains might be something to also try first.

Detroit lockers are annoying and slow going in the rear with a manual transmission, but still doable.
 

WILLD420

Observer
Trutracs are seamless, but you have to know how to drive them. ARB and Tacoma rear lockers are good when you need them, but for an everyday driver, a L/S diff is much better at getting you going from a stop on slick pavement or ice. You can't exactly lock an ARB or other selectable locker while you have a tire spinning trying to get up a hill or on-ramp when it's crappy outside.

I've run Lunchbox lockers, Dana Powr-Lok's, truetracs, trac-loc's, Toyota e-lockers, and open diffs. For me, an open diff is a worthless thing to put on a truck. Give me a trac-loc in the front, if I can't get a selectable or a truetrac. Powr-Lok's are very aggressive if set up right. Between a lunchbox locker and a Pow'r Lok, I'd take a Lunchbox on the front axle in snow and ice, at least when you let off the throttle, they will sometimes unlock if you have chains or good tires on. The Pow'r Lok doesn't.

I've wheeled a little in deep snow and a trutrac sucked. That's why my rig has a lunchbox in the rear now. For mild driving and level 1-4 on a 10 scale trips, it was perfect. When I stepped up to deep snow and more rocks, the truetrac had to go. Wheelspin is not a very good option when you are threading between rocks and trees.

Locrwln and I have done some decent trails in the past and dual limited slips always took more work and made for a harder trip when wheeling anything tight or technical.

Just my 2 cents.
 

Greg5OH

New member
thanskj guys. Il will get the true trac in the front first.

foir the rear heres my concern: driving on a slicky snowy and icy highway. They dont seem to liek to plow the highways up here very often so you gotta make your own tracks. When i had an open rear end on my old CCLB 2wd it was awesome once oyu were going on th efreeway, cuz you could just mash the throttle and bulldoze thru those big 1.5 foot drifts and the thing was straight like on rails. Because only 1 rear tire woudl spin doing 50 mph. Im sure if i did this with a tight LSD or a tre trac or locker i would have to be more careful.
Where i HATED my open diff was starting out from a light, or anywhere remotely inclined up hill. You just COULD NOT get any traction. worthless. Im afraid that will happen with an LSD rear end (i have yet to drive the new truck in the winter). Get one tire on ice (or you spin thru the snow and get to ice) and your going nowhere till i engage the 4x4. Will a true trac work in these conditions? LSD?
Thing that worries me with rear locker is how some people say when you let off the throttle it can wind up and do funny things. Last thing I need is when letting off the throttle in snowy conditions to slowly start braking, and have the rear end unlock and forefully lock again.


regarding chains, ill be ordereing a set but thats if i want to get crazy and actually go offroading, i dont wan tto use them just to drive (not THAT much snow here)
 

Shiryas

Adventurer
In the past I had ARB's on my 95 Toyota Pickup (XCab, 3.Slow, 5speed) and was happy with them but did have air line issues a couple of times. I have driven several Defenders and D1's with Detroits, which are great for off road but I could not live with their on road characteristics.

When I did the axle swap on my 97 F350 (CCLB, 7.3, 5pseed) I went with Truetracs front and rear and have been very happy with them. I wanted something that was simple and low maintenance, no clutch packs, no special fluid, no air lines, no electrics, no snap oversteer on activation. They have been phenomenal in the snow and no issues off road in lots of sand and limited mud. Bear in mind this truck is massive and is the tow, recon, camp rig not a rock crawler but they have worked well on this platform for its uses. I have yet to have an 'open' issue with these differentials as I have read about. I understand the way a Truetrac (Torsen) operates and the necessity for a surface traction difference between the two wheels, I just have not had any instances yet where I needed to dab the brake.

Cheers, Chris
 

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ccarley

Adventurer
After a lot of thought, I went with a True Trac in the rear of my Suburban. A Detroit Locker was less expensive for my axle, but I figure if I'm in a situation where there are tires off the ground, that is too much for this big truck. I'd like to put a True Trac in the front as well, but that is going to be very expensive due to the other work necessary to make that fit.

In any case, torque makes the True Trac grab. When/if a wheel looses traction, torque is lost (at the wheel) and it won't necessarily grab. Little bit of brake will certainly get you going again, if necessary. I've enjoyed the added traction in the mud, ice, and snow so far, with no ill effects. In the rain, if you give enough throttle, it will get tight and the rear can come out, but it's very predictable. In the snow and ice of Tahoe, I was really surprised at how much more traction I had in 2WD.



Where that photo was taken, we had driven about a mile down a road that wasn't plowed. You can see some snow on my front axle, showing how deep it was in parts. When I got out to take the photo, I found that area was completely iced over. I fell down, looked up, and saw the corner of my door heading for my head... thankfully I caught it with my hand before a more serious injury occurred!

Now we will be towing a small tent trailer (off-road included). I still want to install a True Trac in the front, and I bet that will be sufficient for us in any situation that I am willing to take the Suburban into.

Good luck with your decision!
Clay

PS: The True Trac case is pretty beefy too:

 
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Greg5OH

New member
thanks for your accounts guys, I think i will be going with the true trac in the rear. I too dont wan tot deal with clutch packs and such. nic ethe true trac is about 200$ cheaper than the locker. I assume the true trac feels simialr to an LSD where it doesnt snap lock up on you, so it will be a littl ebit more tame when bursting thru packs of snow on the freeway at 50 mph. If i do end up in a sitatiuon wher ei need to apply the brake sa bit, i can always set the parking brak eto drag a hair to give it tha tpreload.
 
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