Can i expect that the diffs would behave like they are now once the ARBs are installed?

 

Yes. If not engaged the differential will remain and function as an 'open' unit.

 

Which what i'm probably experiencing now with a weak limited slip.

Can ARBs be turned on and off while driving?

 

Yes, as long as you let off so you have zero wheel slip before engaging.

 

k...thanks

 

Going to buck the trend here...
I've had many different lockers and find selectables great, BUT not for your use.
Trutrac for a daily driver and even moderate off road.
"Locking up" is great when you have a wheel in the air, burried in a mud hole, or dragging your underbelly over an obstacle but do you really want to be playing with switches as needed driving down the highway.
As noted the arb's are normally completely open diff, but when locked are like a spool.

 

So....should i do the TruTrac in the rear and what in the front?

 

I think you would be happy with either a Truetrac or an ARB in the rear. They both have benefits and drawbacks.

For on-road use, the Truetrac will be better any time there isn't snow on the ground. The ARB will be better (unlocked) in the snow. Not for maximum traction, but for driveability. If it gets bad enough that you need the extra traction, 4wd should be engaged. I wouldn't want to run the ARB engaged on the street at any time, unless you just want to have some fun.

I would be very careful using the ARB (engaged) while hooked up to a heavy load. The axles can only take so much pressure and if you are in a situation where you are loaded heavy and you need to engage the rear locker, you are asking a single axle to carry all of that load. Bang.

For the front, I would absolutely NOT run a Truetrac in areas where snow, mud, or slippery conditions can happen. If you really want something up front, an ARB is the only way to go. That front ARB will not help in most situations. Look at all the off-road Jeeps and Toyotas and other built vehicles out there. When money is no object, both front and rear selectable lockers are installed. This is the best way to go for off-road use. There are times when open diffs are highly advantageous and times when a locker is worth it's weight in gold. The ARB (or any selectable) will allow you to have the best of both worlds, exactly when you want it. Now look at those with a budget (99.9%). Most will have a rear locker very high on the priority list and the front locker is way down the list. There is a reason for this. The front does not provide nearly the same advantage (especially per $$) as the rear.

Unless you are doing serious off-roading, I see no reason to spend the money on a front locker. The $1400+ it takes to buy and install would be better spent on a winch and mount. If money is no object, by all means, install everything.

 

Thanks for the insight. I'm trying not to do the winch, but i may. I don't like the idea of an open diff in the rear (which is what i'd have with an ARB) I'd like to have posi /limited slip so it would engage if needed at any speed. The ARB in the front would give me the margin of safety to crawl out of a difficult spot and yet have an open diff for regular driving(like it is now).

Does the TruTrac make noise when it's engaging? Does it skip when turning tight?

 

The Truetrac is silent in operation. It does not skip when turning. It is a limited slip. It will not positively lock both wheels together. When one wheel is unloaded, it will receive all power. The Truetrac will allow for speed differential during cornering.

The trouble with a limited slip is that it is engaged at ALL speeds. Meaning that if you hit some ice or slippery snow, the back end will have a tendency to kick out. An open differential will allow one tire to stay planted. There is no questions that an open differential is safer and easier to control in slippery conditions.

There is also no question that a limited slip differential, like the Truetrac, will allow for both wheels to receive some power. This makes the truck more capable in low traction situations but will require more awareness and driver input when driving in slippery conditions. Like I said before, there are benefits and drawbacks to going with either route.

Before deciding, it sounds like you need a basic primer on how these devices actually function so you can better understand how they will behave in your use.

A FANTASTIC video demonstration of open differentials: This would be the ARB in normal operation (disengaged).
https://www.youtube.com/watch?v=K4JhruinbWc#t=1m50s

An OK video explaining a limited slip: This would be the Truetrac.

I feel this video leaves out the fact that if one tire is completely unloaded, it transforms into a low torque situation and no force is applied to the clutch packs. This leaves you with an effective open differential once one wheel loses all traction. For a limited slip to function, you need SOME traction on both wheels.

Locked Differential: This is the ARB engaged.
There really isnt a need for a video for this one. Both axles are locked together and spin at the same rate, regardless of any other factors.

 

This first link was great!! I know how it works and why and I understand the second one too. I'm not concerned about the back end kicking out....with or without the trailer on. But i think having one on the front too could set me up for disaster at road speeds.

If i'm stuck on soft ground...the trailer hooked up. One tire is spinning...I know that there needs to be some load on the free tire for the LTD slip to be effective....other than jamming something under it...can you apply the brakes?

Take the same scenario....let's say i have no traction at the rear....my thought is a locker on the front...when engaged...locked hubs....4wd engaged would help me crawl out....then the rear would engage.

Regular driving....winter time...LTD in the rear....locker in the front NOT engaged....truck in 4WD high.....I would have one pulling in the front....and the rear would do it's thing.....Correct?

I've read your post more than a few times!! maybe the safest thing...towing in poor weather IS to have ARB in the rear as well. I can lock it to get out of trouble....once on good ground....unlock it....drive away!! In winter weather...in 4WD....With ARBs unlocked...i have one driving in the rear and one in the front.

 

The stock Ford Traclock is silent, and is limited slip type. I have had Lsd type diffs in my last two vehicles (excursion and tahoe) and much prefer them to open diffs which i had for 25+ years of prior vehicles, including a lot in snow.

In my jeep, i have Detroit truetrac diffs which DO click when they are turning and not locked. They are automatic, in the sense of auto engaging when power is applied.

 

For clarification, the factory Ford LS unit is a Trac Lok... Not to be confused with the Detroit/Eaton Truetrac, or the Dana Powr Lok.

The Trac Lok is a clutch LS with clutch disks. The Truetrac is gear to gear LS, that SHOULD NOT make any noise, and the Powr Lok is also a clutch disk type LS, but can be set up with 90-95% lockup. A Detroit Locker or similar full locker if it's a full carrier type or "lunch box" style, WILL click around corners and sometimes bang at random times making you think something just broke.

Now, if it where me, I'd do a full auto locker in the rear axle and a LS or selectable in the front. I really don't like the full spool effect on the hwy for a rear axle. I've broke way too many parts in rear axles with them spooled or welded on the streets.


I know I originally said selectable front and rear, but after thinking more about it, I wouldn't want a selectable rear. I've ran a lot of full lockers in the rear of vehicles on the streets, never had a issue with them on snow and ice or pulling a trailer.

 

My money is no object solution would be arb's front and rear. I was hung up in the snow last winter and the factory limited slip would not lock up at all and I was left with one tire spinning. The true trac is a great aftermarket limited slip but it will also leave you with one tire spinning, especially if you slide into a ditch. A Detroit or similar isn't a very streetable option for me. Too noisy, too harsh, pain in the *** trying to coast through all turns.

I've had lots of trucks in the snow. 4wd/awd with open diff front and rear hands down is the most stable and easiest to drive without being scary. To put it this way, I want both diffs open to give me the best chance at keeping it from getting stuck. If I'm stuck I want both diffs locked to give me the best chance at getting out. The only reason I don't run arb's in all my diffs is due to cost.

For the front, I never recommend anything but a selectable locker for anyone who wants to run in 4 hi in the snow. Anything else is a bit dangerous and will tend to make it understeer.

 

I've heard many people mention the brake trick. I've tried it numerous times. I've seen people try it numerous times in all different vehicles. I have NEVER seen it do anything. Not once have I ever seen someone get out of a stuck by applying the brakes in any fashion to force power transfer to the opposite wheel.

Correct. If both rear tires have no traction, the front will help you crawl out. If you only have traction on one front tire out of three, the locker will help you out. Rare scenario but correct.

The front would be open, so whether one or two is pulling depends on the traction differential between the two but at minimum, yes, you would have one pulling up front and one or two pushing in the back.

x2 Detroit locker =/= Detroit TrueTrac

Here is a video of the TrueTrac operation.


A spooled/welded/locked rear end will be 100% transparent on the highway unless tire pressures or sizes are significantly uneven. Since both tires are traveling in a straight line with no traction or speed differential, the diff will be behaving in the same manner as an open differential. Both axles will be spinning the same speed.

I agree that there is a higher chance of breaking axles on the street with a fully locked rear. Most likely under hard cornering loads, especially loaded up with a heavy trailer.

Personally, a lunch box or auto locker, like the Powetrax LockRight, are budget only choices. More streetable around tight corners than a welded rear or spool but you trade chirping tires for bangs and clicks. I've run them in the past and hated every minute of them on the street. They unload and bang around tight corners. With such a long wheelbase they are miles better than on something like a Jeep but they still are miserable to deal with. Just my opinion.