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Detroit Trutrac vs Selectable Locker?


RangerSlamz

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Hello,

I have a 1999 automatic 2wd. I'm upgrading the gearing from an 8.8" open 3.55 to 4.10 or 4.30. I will be towing a camper (Say up to 4,000lbs) and going off-road but not for sport. I'm not looking for extreme conditions, I just want to be as prepared as possible. I'll be encountering sandy, desert terrain and maybe occasionally some snowy/icy roads. I will have a winch btw.

What is better all around? A Detroit Trutrac or something like an ARB? I don't really want to sacrifice handling, but I don't want to invest a lot in the ARB if it isn't going to suit my needs at all. I've heard mixed things about both, and I don't really know how to evaluate all the factors.
 


Captain Ledd

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They're not really in the same class.

The Tru-Trac is a high-end limited slip. They work on a function of how much grip the spinning wheel has. The bias ratio is how much it can multiply that grip. generally it's in the neighborhood of 3.5:1. So whatever grip the wheel with the less traction has, it multiplies that by 3.5 to the tire that has grip. However when the spinning tire has very little grip, like on ice, super slippery mud, or in the air, very little or nothing times 3.5 is still very little or nothing.

The ARB is a selectably locking differential. Flip a switch and both wheels turn at the same time and rate, regardless of traction (thus, locked together). If one wheel spins, the other spins. Then when in unlocked mode, it the same as any normal open differential, no handling sacrifice, will drive exactly the same as it does now.

If you're looking to get out of a situation and not mess around, ARB is the way to go.

Plus, having an always with you air compressor, is SUPER useful.

Edit: FYI, I put an ARB in my 2wd. Check the signature :)
 
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gw33gp

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That is a tough call. My Ranger came with Torsen rear differential which is similar to the Truetrac. I like it very much. I tried to find a selectable locker for the front but no one makes one for a Ranger without requiring a lot of modification. I ended up getting a Torsen for the front and am not sorry I did it. I find when accelerating, they work almost as good as lockers. So much so, that I had to change my driving style when in 4WD and accelerating. You can also get better traction by lightly applying the brakes to get the free spinning wheel torque loaded. I can't tell you how well this works because I have never needed to do it.
I recently installed a Detroit Truetrac on my 69 Fairlane Cobra and it works like a charm. Of course, it does not go off-road though.
I think a selectable locker would be nice on the rear of a 2WD Ranger but you should run it disengaged most of the time. Otherwise, it is a strain on the rear axle. Yes, it would be the best in a stuck situation but you are still driving around with an open axle most of the time.
I am pretty sure there used to be a selectable locker that had limited slip capability when disengaged but I don't think they make them for Rangers anymore. That would be the best of both worlds.
 

RangerSlamz

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Thanks guys, I'm still a little torn.


I was leaning towards selectable because If I am really stuck, you're right, I don't want to mess around. And I did like the idea of the compressor.


How much stress is it going to put on the axle? Can I keep it just switched on while I go off-road or am towing without worrying? At what points can I switch it on or off without damage? Do I need to be under a certain speed or something?


What are the handling characteristics of the two? Say compare both in sand, street, and snow/ice. From what I've gathered from other people, the locked axle may want to push the vehicle to one side or the other based on road slope and the limited slip may be kind of squirrelly leading to fishtailing. Any truth to that?
 

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If you can swing the price, I think the selectable locker is the better option. You can leave it engaged while off-road. I, personally, would not leave it engaged while towing on pavement. A locker completely defeats the differential when it is locked. So something else has to slip around corners to account for the different distance that your tires must travel - hopefully a tire on something loose. If the truck is heavily loaded or towing, it will be more difficult for a tire to slip around a corner on dry pavement. Therefore, you will have higher torsional forces in your axle shafts. Being able to prevent that by disengaging the locker would be a great thing.

The TruTrac will act more like a normal differential. It helps equalize power distribution but allows differential action. I imagine that would have better driveability on dry pavement than an engaged locker.
 

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+1 ^^^

Locker is for straight line driving, it can be used on loose surfaces, which allows 1 tire to drag easily when going around a corner.
If tire can't drag then something else has to "give" to allow one axle(tire) to spin faster than the other when cornering.

Limited slip allows one axle(wheel) to spin faster than the other up to a point, so allows cornering, but still provides power to the other axle, unlike OPEN differential.

IMO Limited slip would be better for your described use

You leave locker engaged, by mistake, one time and it could get expensive, besides stranding you
 
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Mac

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Might think about the axle out of a FX4 with the Torson L/S that comes stock with the 4.10 gears, save bit of money.
Dave
 

85_Ranger4x4

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I have a tight clutch type limited slip in mine.

In 2wd on packed snow or ice the rear wants to pass the front bad. Almost helpless to get around really. In 4wd it is a tank when the front wants to stay in the front.

For a dd, a locker on slick stuff would have no appeal to me at all.
 
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Captain Ledd

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^ That would pretty much be the result of driving locked in snow/ice. Sand, it would do better. As for the street, if you're not struggling for traction, leave it off. It will push a little if it's on, you'll feel it, it's hard to describe over text.

To engage a locker (usually/almost-always), stopped is better. Flip the switch, creep forward with maybe just bit of a turn of the wheel to help the splines line up, and then you're locked. Generally UNlocking at speed is fine, but I'd keep it on the slower side, sub 25mph or so.
 

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The feel on the street with a locker 'on' is pretty straight forward. The vehicle will want to go straight when you are trying to turn. You can make it turn but the vehicle will resist your efforts. This can be overcome by spinning the tires but then the back end will try to pass you. Using a locker or limited slip in snow, ice, rain, etc. on smooth surfaces takes a little skill or experience to do it safely. This is especially true with 2WD vehicles.
 

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For the record that wasn't turning, that was trying to accelerate up to speed after turning onto the highway. The crown of the road was messing me up.
 

RangerSlamz

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Thanks for the info everyone. I have some time to think about it before I buy. I think what I'm going to do for now is keep my eye out for an explorer or Fx4 rear axle and then go from there.
 

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The feel on the street with a locker 'on' is pretty straight forward. The vehicle will want to go straight when you are trying to turn. You can make it turn but the vehicle will resist your efforts. This can be overcome by spinning the tires but then the back end will try to pass you. Using a locker or limited slip in snow, ice, rain, etc. on smooth surfaces takes a little skill or experience to do it safely. This is especially true with 2WD vehicles.
truth there. and a spool in the snow can be more predictable on some trucks.....so no simple answer.

I am not a fan of limited slips for certain applications...or most for that matter.. simply too varied for predictability when you need it most...I have had lockrights/detroits, arbs and limited slips of various types along with welded/spools/minispools across a range of rbv and other trucks and cars..

if the axle comes with a l/s I will deal with it until I can afford to do otherwise...generally I will mod the brakes for bias to get by....I wore out the last doner l/s axle without going back to a locker. but I also tend to have massive high traction tires. I have went back and forth with a drop in for the front depending on season.

I currently have a detroit in the shop truck, and it eats tires just the same as it did with the previous true trac. but I know I have reliable traction now.... they broke the rear end(fawkin 14 bolt at that) trying to get unstuck with the tt. it had over a 100 k miles when that happened though. probably never had the diff oil changed.

since you will have a winch, I can see the tru trac.. they are a quality piece...and unfortunately will dramatically increase tire wear along with traction..and take some getting used to in most applications with icy slushy conditions.


with a 2wd...a selectable locker is always my first suggestion if traction is being considered. especially with aggressive expensive tires that will see more road then camping trails.

you will not inadvertently forget your elec-trac or arb is locked. you will know its engaged on high traction surfaces. but they are harder on the axleshafts if you do choose to leave it spooled on the pavement. any weak shackles or rotten spring mounts or weak areas on the frame will make themselves known if you push it.


the fresh axle in my truck is still open. its only a 30 spline 60 so a aussie can be ok for general use under 38 inch with sensible driving. with my current hp level it don't make sense to get an arb. but you have a 2wd.

if I was in a position where I thought I could have a 2wd, I would spend the money on an arb or elec-trac or whatever ....and even if I never used it I would be happy with the investment. probably because I cant see a point where I would not use it in a 2wd...


with all of that babble.....start with the winch....may never need the locker.
 

RangerSlamz

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That makes a lot of sense. I think I will eventually go the selectable locker route. Even though I may not need it, that's better for me than being committed to always having a limited slip. I'd love to personally compare the two one of these days.
 

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