I am on the verge of having the stock differentials replaced in my 2008 F250. I have done lots of research online, read many posts on this forum, and basically I have come to the conclusion that putting Detroit True Tracs front and rear is the best solution.

Here are the facts:

I live where it snow frequently, and have a really long driveway that does not always get plowed. The OEM LS differential really is crap, and I have been stuck more times than I care to admit, even with 4 wheel (2.5 wheel really) drive.

In summer I spend lots of time exploring backroads in the southwest, many of which I need to use 4 wheel drive for. The truck is mostly used for recreation and trips, not as a daily driver.

I found a shop in Phoenix that will do the work for around 2200.00 - both axles parts and labor.

I have considered some kind of locker, but really don't want fulltime lockers like the Detroit NoSlip, and I don't really want to spend the extra for ARB air lockers or E-lockers.... besides Eaton apparently doesn't make an E-locker for the 10.5 rear end, although there is one for the front Dana 60.

I know opinions are just that, but before I make the call to schedule the installation I would like to hear some feedback from the learned members of FTE.

I appreciate the advice.

 

I haven't had True Tracs in a Super Duty. I had them in a Jeep Wrangler that was built specifically for trails. When I put in the True Tracs it was a street Jeep and I assumed at some point I'd put in Detroit Lockers front and rear. I ended up moving to So Oregon where we get four true seasons, snow and ice and hot and dry.

When I first got the True Tracs I was on a (Southern Calif) Jeep run with many Jeeps built much more offroad minded than mine was at the time, and after a particularly difficult climb out of a creek and up the side of a rutted hillside I had a spotter stop me and ask what kind of lockers I had. He was very surprised when I said I had limited slips. On that same run there was a difficult, rocky, section I wanted to try. Another spotter said, "No way man." I told him I wasn't concerned with making it or not, but I wanted to try it out. I lifted a wheel, crawled slowly over boulders and made it through with the spotter pretty wide eyed. He too asked what kind of lockers I had and couldn't believe I made it through that section with limited slips. This had happened a number of times while I had my Jeep, that I was running with the "big dogs" and they all wondered how the little Jeep could keep up. I then started building the Jeep to be more offroad specific and decided I'd put in Detroits front and rear when I needed them. I didn't need them for the trails in Oregon, and they actually worked better than lockers at times in the snow (I wasn't as likely to side-hill/crab-walk).

So, again, I haven't had them in my Super Duty, but they are what I'd put in if I was going to put something other than selectable lockers. True Tracs are not lockers and never will be, but they're in my opinion, the best limited slip you can put in a vehicle that's going to see moderately difficult four wheel drive trails. If you've got decent tires, the next step is limited slips or lockers front and rear.

 

Now that's a heck of an endorsement!

As Ace alluded to, the biggest negative to a true locker is the tendency to slide sideways or spin out in very low traction situations, especially on a side hill! With the diff locked, both wheels will start spinning at the same time, so any side forces (inertia or gravity are biggies) will result in that axle breaking loose. With an open diff, usually only one wheel spins so the non spinning wheel will still be gripping the road and is less likely to slide sideways.

For just that reason, I MUCH prefer manually selectable lockers for icy roads. Turn it on only when it's needed, turn it off when making turns or on slippery side slopes.

The True-Trac, if you operate correctly, will behave quite similarly. If you stay light on the throttle, it works like an open diff giving you side slip stability. If everything is good and straight, you can apply more torque and have it start gripping. And as Ace reports, they will grip pretty darn hard in high traction situations.

Personally, I think a True-Trac in the rear and the E-locker in the front is the ultimate set-up for anything but hard core off-roader. I really like having absolute control in the front diff. I like leaving the front axle TOTALLY open as much as possible as it reduces drivetrain and steering stresses. And when I need it not open, I REALLY need it not open and want it truely locked.

 

From everything I've read, the TruTrac seems to be the best limited slip you can buy.

I've had personal experience with Ford OEM clutch-plate limited slips, Auburn cone-clutch limited slips, but not with the gear-driven TruTrac. The Ford limited slip is really poor, as you mentioned OP. Even on level ground, I'm never sure if both wheels will spin. I'm real close to draining the axle lubricant and refilling without the friction modifier. Hopefully, that will help the clutches grip better until I can get an aftermarket traction aiding differtential in the rear axle.

The Auburn, on the other hand, is much more aggressive. It would drive both tires equally up until the point a tire came off the ground or unloaded big time. Then, it would slip just like a open differential. The Auburn would get sideways in a hurry on a rainy street if I was heavy on the throttle around sharp corners with mud grip tires. The glaring disadvantage to the Auburn limited slip is that the unit is non-rebuidable. Mine lasted 75,000 miles of moderate off-road use before its performance noticable degraded.

The reason I believe the TruTrac is probably the best is because it doesn't need friction modifier added to the lubricant and it won't wear out or lose its torque biasing ratio as the miles add up.

The only other piece I'll add is that a limited slip differential's ability transfer torque seems tied to the weight of the vehicle it's installed in. Will the TruTrac be able to drive both tires as effectively in a 7000lb Super Duty as a 4000lb Jeep? My Auburn felt much more aggressive when the pickup bed was empty than when it had load of shell corn for the deer feeders. The F150 pickups with the OEM limited slip seem better than the Super Duty limited slips- maybe because the F150 is lighter? I know that the clutches in clutch-based differentials can only "hold" so much before they slip. The TruTrac is different by design, so I have no idea if that's even something to consider.

Regardless, front and rear TruTracs are going to be head and shoulders above the stoct set-up. Please post back here with your results.

 

So far so good - please keep the comments coming. I do like the idea of an E-locker in the front, but I am not keen on the extra cost or the necessary wiring harness. How reliable is the electromagnet set up - reading the manual give the impression that it could bind on engagement/release under certain circumstances? Again I am not looking to turn my SD into a trail monster, just to get through unplowed snow and run some trails.

 

I run a Tru-Trac in my rear end for snow plowing. Last year I had an open diff. Big difference! *** wants to slide out a little bit more sometimes when pushing, but it is nothing less throttle won't solve. Much better traction, I run in 2wd in places where I had to have 4 last year. Definitely worth the money.

P.S.: My mechanic told me it would be a waste.

 

I also added the true trac to the back axle, and haven't looked back. Def an option with price being the deciding factor. I really wanted the arb front and back, but couldn't justify the cost for what I do and ended up with the true trac and couldn't be happier.

 

$2200 for the true tracs? Sounds a bit high, can't you get the arb"s installed for that?? or real close anyway.

 

Axle work has always been pretty expensive in my experience. Not every mom & pop garage wants to set up a ring and pinion. So the labor has been kind of what they can get away with since few garages do that kind of work.

I bet a garage will charge 3-4 hours of labor per axle. And if they charge $75/hr, a customer might expect $500 just for labor. Add another $1200 for the TruTracs + install kits (bearings and shims) + "shop expenses" will get you around $2000.

Expensive, true, but I can see it.

 

Cost breakdown for the install:

Parts Front: 620.00
Parts Rear 580.00
Labor: 840.00
TAX: 120.00

Total 2160.00

I priced the True Tracs from several different sources, these guys had one of the better deals. Labor is as Labor is.... The price you pay for asking someone else to do the work. I don't have a shop or place to work on the truck this time of year (winter, you know) and I don't have any of the specialized tools needed to work on the axle.

As a shade tree mechanic, there are some jobs I don't mind letting someone else do.

 

More money than I thought, have you priced out the arb's?

 

sorry, don't mean to hijack and this is probably a NOOB question but exactly what components does the true trac replace in the diff? I am wondering because i was looking into them as well, but i also want to go from 3.73 to 4.30 or even higher, so i am looking to "kill two birds". Do you just trash my 3.73 and purchase a 4.30 true track and call it done, or do you need other 4.30 gear parts to work with the true trac?

 

You'd need pretty much all the differential parts. The TT replaces the "carrier", but with your 2003, you'd need ring/pinion and likely want to replace other axle/differential parts.

 

What type of sound, if any do you hear from your True trac? I just had mine installed, I hear a slight, sandpaper sound from the rear. Also, the housing was warm to the touch. I never touched it before, so I am not sure how warm they get normally. I called the shop that installed it, he wants to see it again in the morning. Just curious to hear what your experiences have been.

 

I didn't hear sounds from the True Trac. I think it's the gears wearing together/matching up (the ring and pinion) if you're hearing things and getting warmth. Warm is normal though, hot would be normal at first. The gears will kind of set, and as they do they will generate plenty of heat. My thought, although everyone is different, is to put 500 miles on it relative easy going, then change the gear oil and then, hammer down.