Hey All,
'07 FX4 limited slip axle w/3.73s @106k. Do these limited slips wear out over time? How aggressive is it compared to a posi axle? I was backing up my driveway that has an incline and my pass side tire was on ice/snow and the driver wasn't. The pass side was spinning really good and the truck stopped.
There isn't any noise coming from back there and I just had the diffs and Xfer case fluids changed w/Amsoil. I was told that the gear oil comes w/a friction modifier in it.
Any ways, does the limited slip deteriorate over time?
Does my VIN tell me what I have for a rear end?

 

The Ford traction lok is almost identical to the old chevy name posi-traction. Both use clutches and springs to lock up the rear wheels when the vehicle is in snow, ice, etc. They are not heavy duty enough for rock climbing and yes the clutches can wear out. My 2000 truck had the traction lok and it was still working well at 170k miles. My current 02 has a traction lok unit and it works great at 129k miles.

If you spin one wheel like you just described, you will wipe out the clutches really quickly.

The code on the door sticker and the tag on the rear diff will tell you if you have a traction lok unit.

 

If the door sticker code is a letter and a number it's LS, if it's 2 numbers it's open.

 

OK, on the door sticker it says B6.

I don't want to pirate my own thread but the other headings on the door sticker says:
Axle: B6
R: B
TR: Q
SPR: TTMM
Int Tr: RB
TP/PS: is blank

It feels like it is working. For example pulling out of my driveway it is a hard 90 turn and it feels like there is resistance and that a tire wants to break loose (the different radius w/the different rotational speeds). But backing up the driveway and the pass tire is on ice and the other 1 on hottop, I would think the tire on ice would spin while the driver would keep me moving slowly.
I don't get stuck all the time. If i back up w/very little throttle I can make it up using very little momentum.
Is there a definitive test to see if the clutches are still in working order?
Is there a mod to make it a little closer to posi?

 

If you make a 90 degree turn and step on it, the clutches will either lock up or you will feel them trying to lock up. B6 should be a 3.73 traction lok.

 

Is there a ford equivalent to the T80 Eaton that GM uses?

 

Anyone care to explain a bit more about the clutch based LSD?

 

I think you mean G80. There is no Ford equivalent to it. I had a Silverado with one and it was miserable for normal driving and even worse for rain-slick pavement.