this is on my 2006 F-250, I have confirmed it was equipped with a 3.73 LS rear diff. it doesn't appear to be locking anymore, only 1 wheel is spinning.
Is there anyway to correct this? I know Ford sells traction lock rebuild kits for the 8.8" rear diff in cars and F-150s

I looked at several aftermarket units, like the lock rite unit from Richmond gear, but no one offers anything for this rear diff with the 3 pinion carrier.

POWERTRAX® LOCK-RIGHT LOCKER BY RICHMOND

so, any ideas how I fix this? I want some sort of limited slip or locking rear diff.

rebuilding or repairing the stock unit is preferable, but if I have to replace it with a aftermarket, I will consider it.

Eric

 

You could try new oil without friction modifier, and see if the old unit will lock up at all before putting in a more correct amount of modifier.

Eaton TrueTracs and Detroit lockers are popular, the stock Auburn unit is kind of a POS, notorious for the clutches burning out.

 

Once you've burned out the stock LS, which is what has happened, I would not rebuild it with OEM components. It just isn't worth polishing that turd. Either do without LS, or step up to a TruTrac.

 

As much as it pains me, I have to agree w/ a red raider. Bryan is correct in his assesment. I've got a 2005 w/ the same rear and the same problem. I'm almost due for an oil change in the rear anyway so I'm going to try it w/out any modifier and see if it works and if it chatters going around corners - if it works but chatters I plan to add the modifer in small amounts until it stops chattering. If all of that fails I'm putting a trutrac in. It's really disappointing b/c I have a '95 F150 w/ the factory limited slip w/ almost 160,000mi and that thing still works amazingly well.

The theory behind all that is there was too much friction modifier installed from the factory and it lets the clutches slip too easily. Whether removing it will work remains to be seen. Personally, if yours is shot, I woudn't suggest rebuilding it - it's still a clutch system and prone to failure. The TruTrac is a gear drive system so it's much more robust and reliable.

 

my 06 has a whopping 10,000 miles and I know for a fact that my LS is pretty much dead already. When i got stuck over the weekend only the drivers rear tire was spinning. As previously mentioned, the F-150 LS is a much better unit. My 2006 was supercharged and the 9.75 axle with LS held up to tons of abuse from me on/off the road.

Tru-Trac replacement is my solution when I get new gears

 

I would be all for a tru-trac... but I don't find a listing for the 2006 F-250 with the 10.5" rear diff.

 

10.25 & 10.5 Detroit True-Trac Differential


Part Number: 915A550 (ff)

http://www.eaton.com/ecm/groups/publ.../ct_128302.pdf

 

https://www.ford-trucks.com/forums/1...c-install.html

 

I'm bringing up an old thread fellas, but want to tell my story to see what you think. My LSD was working fine. About 3k miles ago I had the entire truck serviced for the 60k mile service and they changed the sythetic fluid very early at my request. I thought I've almost noticed a slip when accelerating just off dead stop then it goes away. Today it actually rained so I'm poured the coals to her on a wet street (didn't wanna do it on dry pavement just because I don't like stressing it like that) in a slight right turn and it was peeling just the right tire the entire time. Is mine shot? Should I change the fluid without the friction modifier. The truck had an easy life. Is it just a POS diff. It's still under warranty so I can take it in to get it fixed if need be but I hate dealing with the stealerships.

 

It's a turd LS, like everyone says. Mine was trashed before 60K, and I don't do anything crazy. Stepping up to a tru-trac was outstanding.

 

I have heard about someone taking theirs in for the LS and the tech put the front tires against the curb and tried to spin the tires and when they didn't spin said its working fine?

 

I'll kill em! I have an inboard camera, they that without me knowing about it even if I'm not there. If I ever saw that I would be extremly pissed. They better be opening it, putting a dial indicator on the ring gear for backlash, checking for pinion depth, and checking clutch wear with some feeler gauges. I can't see that on my camera but I'll damn sure see that test if the do it.

 

I had the traction lock in my truck rebuilt in November. it works now, but not as well as I would like it to. eventually, I will get a true track in the rear and a e-locker in the front, might go to a 4.10 gear too.

 

That sounds like mine is from new. The stock LS unit is pretty pathetic. Even on wet grass you can get it peg leg sometimes. I agree with what was said "not worth polishing a turd, get a Truetrac".

 

Ok. I do like the gears better than the clutch packs. So FX4 equals ugly skinny little skid plates, turd limited slip, and sticker that is welded to the bed and refuses to come off nicely? Got it! Oh well, it was on the truck when I bought it. NICE avatar by the way!