I just bought a 2000 F-150 w/3.55 limited slip (28K miles). I got stuck in the ski area parking lot today. I looked out and my drivers side wheel wasn't spinning at all. Doesn't this mean my axle has a problem?

Is getting stuck like this the only way to tell if its bad?

It seems other are having problems, do Ford LS axles suck ? If I fix it under warranty will it simply go out again?

Why does Ford say changing tire size (my tires are stock) can damage your axles?

Thanks for your help,
glasswave


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F-150 XLT Super Cab Long Bed, 4x4, 4.6L, Auto, 3.55 LS

 

Next time you are in this situation, try putting your park brake on a bit... This should create enough resistance to activate the clutches in your differential.

Cheers.

 

Limited slip vs. posi. What's the difference? If I put limited slip into my 4x2 would I notice any difference when driving normal pave type roads? By the way, is there a cool way to put on the brake slightly while trying to not drop the clutch?

 

[font size="1" color="#FF0000"]LAST EDITED ON 13-Mar-01 AT 01:02 AM (EST)[/font][p] Oops...park brake...its late, honest.

 

[font size="1" color="#FF0000"]LAST EDITED ON 15-Mar-01 AT 12:09 PM (EST)[/font][p]Limited slip is the type of differential you have, posi is an abbreviation of the term posi-traction used by GM, ford uses a traction lock. Both do the same thing. Kind of like Kleenex vs tissue paper.
As for the parking brake thing you can apply it while the wheel is turning or before you release the clutch. It does work.

Regards

Jean Marc Chartier

00 F-150 XLT SC Flairside 4x4 4.6 w/5spd
Warn XD9000i, skid plates, Draw tite class III,
Rancho RSX Reflex shocks,
Borla Cat Back
Modified Air Cleaner Outlet Tube
and air box, K&N air filter,
Superchips

 

look at your window sticker,, maybe u dont have it .

 

[font size="1" color="#FF0000"]LAST EDITED ON 06-Aug-01 AT 05:30 PM (EST)[/font][p]Just kind of think thru things here. The idea of a differential is to allow the wheel on the same axle to turn ant different speeds and yet allow both to be "driven". As you go around a turn, the inside wheel needs to "slow down" and the outside wheel needs to "speed up" relative to the centerline speed of the vehicle. The "cluster gears" or "spider gears" allow for this exchange of speed. When both tires are biting well, power is transmitted to both wheels as you drive forward, but if one wheel starts to "slip" or break loose, the car "thinks" it is in a tight turn and allows the free-spinning tire to "speed up" at the expense of the other tire. This is the "stuck-in-the-snow or mud" scenario. To overcome this problem, manufacturers developed their own proprietry systems for allowing only "limited slip". There are variuos names given to these devices (Detroit locker, Posi-traction, LSD, Limited slip, Thorsen differential) just to name a few. Basically they all allow a differntial to "unlock" when there is very little torque applied to the drivetrain (decelerating around a corner or simply coasting) but "lock up" when you jump on the gas and some resistance is felt. Hence the suggestion to apply the parking brake slightly. Under normal driving conditions the LSD offers very litlle if anything. If both tires are developing good traction, there is nothing to be gained. On the other hand, accelerating around a curve usually results in one of the tires having to break loose and "spit gravel" or squeal the tire. After all, the differential will "lock up" due to the acceleration and the curved path dictates that the wheels have to go at different speed to turn the corner, so something has to give. I'm also not a fan of LSD on slick roads; if one wheel breaks loose they both break loose. With the convetional differential if one breaks loose the other will continue to "freewheel" and provide some directional stability. Drag racing and pulling trailers in mud seem to be the best applications for any of the LSD's.
Disclaimer: Just my humble opinion
Oh, the reason about tires size is you don't want different tire diameters on the same axle when using limited slip differentials. You can have larger or smaller tires, just make sure both are the same when placed on a LSD axle.

 

Putting different diameter tires on a LSD axle makes the two axle shafts turn different speeds. The LSD clutch pack, which is across the carrier, essentially axle shaft to axle shaft, will have to slip constantly, like going around an endless turn. When the clutch burns out, you will have an "open" style (non-LSD) rearend. Would have to replace the clutch pack to get LSD action again.