I'm looking to buy either a 99 F250 PSD, or a 2002 Excursion PSD, both have the Sterling 10.50 rear diff. My question is what kind of options do I have for rear lockers/lsd? I've been looking at the Detroit Truetracs, and the Auburn ECTED.
According to their website, the Truetracs are meant for medium loads, and are always activated (no electrical components), and have 100% torque transfer ability. That sounds great, but what does that actually mean?? Will both tires spin if I'm stuck in 3 feet of snow, or will I be stuck with one tire spinning stupidly?
As for the ECTED, it says it can be turned off, and when it's not activated it functions as an open diff. So when it's activated, does it send power to both wheels, or is it just a limited slip again? Will either of these be able to put up with the extra weight of the powerstroke diesel engine?
This will be a daily driver, but I like to go have fun in the snow covered fields behind my house, and it gets up to 5 feet deep in some spots , I'm more concerned about getting stuck in the little 1-3 ft deep stuff, that's what I have to make through to leave my driveway!

Also, what kind of diff does the Excursion have in the front? I know the F250 has the Dana 50, which I can't find any good LSD for... I would love having full lockup capabilities in the rear, and a LSD for the front.
Thanks for all the help!

 

The Tru Trac is an torsen automatic limited slip that, unlike most other LS units, will transfer the torque evenly between both axles (50/50) even when one wheel is in the air, as opposed to an open diff which will transfer 100% of the torwue to one wheel. In my opinion the tru trac is the best automatic LS available, it gives you the traction of a true locker when you need it without the clunky engagement that comes with an automatic locking diff, and it drives on the pavement like an open diff.
A manual locker is great for off roading but they are almost useless when it comes to daily driving, most of them disengsge at a certain speed and if you have it locked and you happen to hit dry pavement while turning things get ugly.
If you go with the tru trac you will be happy and I doubt the powerstroke would hurt it.

 

Wow, sounds like the TrueTrac is exactly what I'm looking for! If I did go with a 100% locker in the rear, it would be the ECTED, which I think gives the same advantages as the TrueTrac, but only when you have it turned "on"...
Do you know what kind of front diff is in the Excursion?

 

The main difference between a locker and a LS is that a LS will allow the axles to spin at different speeds so when you are turning the rear wheels will not try to push the truck straight like a locker will.
I think Excursions have a Dana 80 front axle. If you are thinking of adding a traction aid to the front diff then you should go with a manual locker for saftey, automatic traction aids make steering difficult when they are used in the front diff and most shops will not install an automatic traction aid in the front diff because of it. I prefer the air operated lockers because in addition to being able to lock the diff you get an on board air compressor for filling tires.

 

having an onboard air compressor wouldn't be too bad of an idea... I was reading about the Truetracs, and they said they work fine in the front too. I found a guy on Youtube with them front and rear, and he said the vehicle works perfectly being his daily driver. He said he wishes he had gone with ARBs or a detroit in the rear for more performance off road.
As for the diff, a few people told me it's the dana 50 in front, which I don't really want, not many options for upgrading that diff...

 

A dana 50 seems small, I think the excursion uses the chassis as the Super duty and thought the SD's had either a Dana 60 or 80 up front.
I have never driven anything with a tru trac in the front diff but I have driven one with a LS and it was a pain in the a$$, you had to hold the steering wheel tight and make damn sure your thumbs were on the outside of the steering wheel because every time the LS transfered torque it went through the steering wheel. with the ARB locker it wasnt nearly as bad.

 

My expierience with the Detroit True Trac was this, I put it in a 60 rear went down the road 1/2 mile went to turn around, it made a loud noise in reverse, made a loud noise into drive. Went back home, found the drive shaft was now turning 2/3 of a turn before it caught. Took it back out sent it back. I had no trouble getting my money back. I didn't want another one after that. I never got to use it but as I recall to make it lock up you had to feather the gas to get it locked up & to keep it locked up. I'd stay away from them.

 

Wow, so far you're the first person I've found that didn't like them. I was really hoping they'd be "perfect"..

 

Sounds like the unit was not set up right and the teeth were not meshing up right, they are a pain to set up correctly. As far as feathering the gas to get the unit to engage, that is how they are designed to work, if there is not torque input to the unit then there is no torque to transfer.

 

Could you describe how you would set one up?

My experience with them has been not so satisfactory.
Any, and all LS units are just that "Limited Slip". Eventually they reach a point where they have to give.
Even the manufacturers description of a tru-trac describes it as a simple limited slip.

These units seldom work as described. They are decent, but,,,,,,,,,yeah, thats it.

 

I'm not Quite sure what you mean about "set up" ? There is no set up with the unit itself, it comes completely assembled. As far as setting up ring & pinions I've done them for years & years & that would have nothing to do with the unit failing. I guess I just got the lemon

 

I guess I should have been clearer about setting the diff up.
Did you check the ring and pinion for proper engagement and backlash? Your experience with the tru trac is the only bad one I have ever heard of, when you pulled the unit out did you see any damage? I am curious as to what failed.

 

Like I said I've been doing rear ends for years, no trouble there setting up gears.
There didn't appear to be anything wrong with it, no pieces anywhere in the case. I didn't take it apart because they wouldn't have taken it back. When I talked to Detroit all I could get out of the office person was that it broke & I could get another one or get my money back. I wasn't willing to try another one at that point.
I still have the owners manual for it. It tells all about it & has a exploded view of it. If you want it to look over send me a pm. I don't need it for anything.