Could someone please enlighten me on the ramifications and cost of installing some sort of slip limiting device on the open front diff of my Supercrew? Also is it a do it yourself job, etc.,. Any info at all would be helpful.

Thanks.

 

If I were you, I wouldn't do this job myself unless you have a very capable garage of your own. It's not something that you can crawl under and do in one afternoon. You have to worry about removing the stub axles, drilling the diff case (for ARB), installing the unit, and putting it all back together correctly. The pluses that you get out of installing a LS or locker are great... you can go many more places than you ever thought. Personally, I'd go with the ARB because (if you are a big off-roader or have a farm) you have onboard air. That can be a big benifit. If you're just looking for a little more traction in some sticky situations, go with the LS... it's cheaper and it functions quite well when you use the brake pedal to engage it properly.

 

and... cost... a good LS might run you about $350 plus installation... an ARB unit costs about $675 plus $450 for electronics and compressor, and installation.

 

Screwdriver,

You are in deep doo-doo if you rely on my advice solely, so I would hope you wait to hear from responses from more knowledgeable members....

Anyway, I distinctly remember that auto lockers (not including ARB) are not suitable for front use with center disconnect systems. The reason is that the side not split by the disconnect will undergo drag (because it is locked).

I would guess that this would apply to an lsd in the front. The side not split by the disconnect (the left in your Ford) will undergo drag because it will be turning the entire carrier that it is clutched to (as opposed to just spinning the spider gears and thus the right side gear in reverse).

I hope someone can tell me if I'm right or wrong.

 

Thanks to both of you. Very useful and informative. I don't need it every day but I do go hunting once a year in the swamps of Alabama and it would be very poor form to get stuck in a logging trucks' rut in view of a Chevy or a Dodge driver.

Any thoughts on the Powertrax locker or anything else guys?

 

Screwdriver,

I guess that would be embarrasing. You're are probably less likely to get stuck if you have a ls in the rear already, but I can understand that you would want the best chance possibe if you are going to undergo extreme conditions (even if it is once or twice a year). That's really the entire reason I got the ls in my rear diff, because I didn't want to wait until the times I needed it to realize I should have got it.

I wish Max Mitchell was replying to some of this, as he is the one that pointed me in the direction of the Powertrax, and I myself will probably venture towards something of that nature when my factory warranty ends.

Anyway, the Powertrax, which is a locker not a limited slip differential, is compatible (or claims to be) with the center disconnect system Ford uses (you can see the applicability chart on the webpage). However, I still can't figure out how there wouldn't be some drag while you are driving along in 2wd.
The left front will still be pulling extra weight while the right front is completely disconnected.

It seems an ARB would work just fine, since it's an open until locked. But I guess the Powertrax is a lot let cheaper and you don't have to think about turning it on and off. Maybe you could contact or email Powertrax and ask them how there is no drag with center disconnect with front Powertrax modified diffs.

 

I'll have to search for this one... I recently read that there is a special locker that functions both as an open and a locked differential without having to push any buttons or flip any switches. I'll have to dig out the magazine, but I believe that it was made by the same people who make the Detroit locker.

You may want to consider a gearless locker in back and an ARB unit up front (for when the going gets really tough). That way, you'd have a constantly locked rearend, and the choice of whether or not to lock your front end. ARB units are expensive, so that's why I would also suggest this setup. A gearless locker may run about $2-400, and they serve the same purpose as a geared locker or an ARB unit. The only disadvantage is that you cannot unlock it at the push of a button. As cpadpl pointed out, I'm not sure if you can put a full locker or even a LS in the front without damage to the 'case.

I know that when I have the money to burn, I'm gonna go with an ARB unit in back and slowly work up to a front unit. The big benifit is that you have onboard air... that can be a life saver if you need to air down for your trail running.

But don't over do it. If you only go once a year, you would be suprised at the benifit of a locker in the rear would do for you. You most likely wouldn't need a front end modification, and you would have year-round benifits. Better traction in the rain on slick streets... snow in the winter, and the like. No point in spending $1500 on ARB lockers front and rear when all you really need is a solid locker for the rear to get you through the tough stuff.

Hope this helps some more...
-Flea

 

FleasF-150,

I would concur with the ARB up front. You very may well have read about that open diff/locked diff combo, and that is what Powertrax is. TracTech (maker of Detroit Locker) also makes a very similar item (so similar there is a lawsuit going on between TracTech and Powertrax) called Detroit EZ Locker. These units are simply better designed Detroit Lockers. They use couplers to make disengagement of the unit around corners and subsequent re-engagement completely undetectable (so they say). Very easily installation too.

If you can find the thread in transmissions (I know, wrong forum) where Max Mitchell basically walked me through every type of traction-aid device known to man, you can read more detail. The problem with putting any type of locker in the rear-end is that any type of diff that goes in the rear has to accept an ABS excitor ring that is used on the late model Fords 3-channel ABS system. Therefore, you're only options for the rear are 1) Ford Motorcraft Limited Slip, 2) Auburn Gear Differential (which is a limited slip), 3) Powertrax Locker or Detroit EZ Locker (because these installations simply remove the side and spider gears, not the diff carrier).

To my knowledge, ARB is not ABS compatible. You can put it in, but the excitor ring won't fit on the new diff carrier, and you will essentially have two-channel FRONT ABS. If you ever have to break hard on a slick surface you'll be spinning. The gear type limited slips you were mentioning (Detroit's TrueTrac and Torsen/Gleason) are also not ABS compatible with the Ford truck.

Let me know if you find anything to the contrary, as I would love to be able to put a Torsen in the rear.

 

Thanks for the info... I didn't know that the gears were not compatible with Lockers/ARB's. Looks like I'm gonna have to save longer for different axles with my ARB's!!

 

I have contacted a number of differential distributors looking for a limited slip or locker for the front 8.8 on my 99 150. Randy's ring and pinion suggested the True trac locker which as cpadpl said, should be unnoticable in the daily driving. If cpadpl is correct then this would not work on the ABS system of the fords. Please help as I am in the process of buying new gears for the truck.

 

klaibs27,

I'm not sure if I understand what your question is, but I think I do, so I'll answer what I think you are asking. In all the back and forth I may have not been clear in which axle I was talking about. This is my understanding -

Rear diff - Anything will work, as long as it accepts the ABS excitor ring. As far as I know, the only things that will do that are two limited slips (Ford and Auburn) and any type of locker that does not remove the diff carrier but only alters the side gears, pinion shaft gears, etc. (Powertrax and Detroit Locker).

Front diff - There is no ABS excitor ring on the front diff, the ABS sensors are at the two front wheels, thus no need for the differential to accept an ABS excitor ring when you are talking about the front. The problem (as I understand it) is that the front wheels are activated into 4x4 with a center disconnect system. This means that upon 4x4 activation, vacuum pumps clutch up your front drive shaft and right side gear and axle. When in 4x2, the front drive shaft does not rotate, the front diff carrier does not rotate, but the left (and right) axle shafts do rotate, spins the left side gear, and thus spins your right side gear in reverse (while the right side gear is disconnected from the right axle shaft). Thus the problem - anything you install that locks the left side gear to the carrier is going to force the carrier to revolve when you drive, creating an unusual pull to the left front while driving down the road. An ARB would obviously not have this problem. I believe it was Flea that was stated that the Powertrax website said that their product is good for front diffs with center disconnects. My response is I can't understand how their would not be drag, even with Powertrax. I do not know enough about Torsen/Gleasen to know whether it will work in the front diff.

 

I have the LSD in the rear so I'm not very inclined to modify that. Yet. Anyhow, given the weight of the front end on my truck I thought that a LSD for the front would provide substantial traction benefits in mud etc., yet allow easy street driving which is what I do mostly. The idea of air compressors and lockers etc.,(while good thoughts) are more than I want to do to my truck. I would have ordered a Limited slip for the front had it been available. I know it is not the same as a locked diff but it would provide good traction, nonetheless, on occasion it was needed.

Thanks much to all and any more info would be appreciated, the knowledge here is impressive.

 

I just emailed Trachtech, the makers of True trac as well as Detroit lockers. I asked if their truetrac would work in the center disconnect systems that are in our IFS trucks. Once I get a call or an email back, I'll post it here for all of our use.

 

I would be very interested in the results, as I believe that is essentially the same as the Torsen/Gleason which I would love to have, but don't know enough about the crazy gearing arrangement to know if it would work. I do believe in the TracTech application PDF they do mention that none of their products should be used for the front diff on-highway vehicles unless they have completely unlockable front hubs. Unfortunately, that tells us little since the late model Fords don't have locking hubs anymore.

I did receive an Email back from Powertrax, but like most of the emails from companies, they didn't read my question and didn't answer it. I essentially got that the rear wheels drive the vehicle while in 2wd, and once in 4x4 the Powertrax would work. Where do they get these people? I thought 3 wheels drove in 2wd.

Anyway, I don't mean to be an annoyance with the center disconnect issue. I have read this in an article, it's not something I made up. It was long and drawn out about how some people hail the center disconnect system as the greatest thing of all time (e.g. you don't have to drive backwards to unlock the auto hubs), and some think it's the worst thing in the world (i.e. bad handling with a locker up front).

Max Mitchell did reply to this thread, stating that he personally wouldn't recommend anything up front, but he didn't want to get into it because this stuff always starts arguments. I attempted to reply to his reply, and in the process blitzoided his reply and my reply to his reply....

Keep us informed, Klaibs27, as I am truly on your side - I own a Ford truck too and I want as much traction control as possible.

 

I just called Tractech because they were a little slow getting to my email. I talked to Brent there who seems to be their head tech guy. I asked him if the Truetrac was compatible with the central disconnect systems and he told me that it was not recommended. This was not because of the pull to the left but because of the removal of the c clips that hold the axles in place. Without these, the axles could, and i mean could, wobble a lot. He said that some stores out there have a way of holding these in place. Randy's was one of these stores. They use a spring to hold the axles in place. West Coast differentials has a fax that they send out with their truetrac explaining how to put this spring in place. Talking to Brent some more, he explained that he personally had not experienced the truetrac in a ford front but he had put one in in a jeep with the dana 40 which has the vacuum disconnect as well. He said you couldn't tell it was there because it is a torque sensing device. As for the pull to the left, he said that was basically a falicy and if anything there was a very slight drift to the left because the gears are turning. That's all I have for now. As for me, I think i'm going with the Truetrac up front with my 4.56 gears.