I just bought a 2001 Screw f150 4x4 offroad pkg and am trying to figure out how the limited slip works, and if it does. I've been reading here and can't really decide how to do it. It says I have the axle code h9 on the door panel and trackloc on the truck spec sheet.

What are some ways I can tell if my limited slip is working properly? It's supposed to work in 2wd and 4wd correct?

Thanks!

 

it'll have the potential to work anytime you have power going to the rear axle. if you can find some ground where you can spin tires on, sand, wet grass, soft bare ground, etc. the wet grass works best. just spin your tires and if you have 2 tire spin marks that means both tires spin. if not then the limited slip isnt working.

another method is to jack the rear axle up enough to get both rear tires off the ground. CHOCK the front tires! take off the P-brake and put truck in neutral (out of gear) with the truck OFF. if you spin one tire and the other spins the opposite direction your L/S is working

-cutts-

 

i think you meant if the other tire spins the opposite direction then your L/S isn't working. L/S would have both tires spin the same time the same way...

 

the only way to properly tell if your ls is working is to find a big mud puddle. drive into the middle of it, and stomp on the go pedal as you turn the steering wheel full lock. watch to see if you are throwing a mud rooster tail.
if you are sitting there stuck in the mud with only 1 tire spinning, then your ls does not work.
if you are throwing 2 nice rooter tails, sliding sideways, covering anything and everything with mud, then your ls is working properly.

 

Actually, the truth of the matter is that there is actually a SPECIFICATION for this. Laugh at me all you want, but it's true. The procedure is to remove the wheels and attach an adapter to the lug studs. Put the transmission in PARK and use a beam or dial type torque wrench to measure the "break-away" torque required to initiate axle rotation.

In other words, there should be quite a bit of force required to cause ONE rear tire to turn if both are off the ground and the transmission is in park.

Cody

 

[QUOTE=cleatus12r]Actually, the truth of the matter is that there is actually a SPECIFICATION for this. Laugh at me all you want, but it's true. The procedure is to remove the wheels and attach an adapter to the lug studs. Put the transmission in PARK and use a beam or dial type torque wrench to measure the "break-away" torque required to initiate axle rotation.
In other words, there should be quite a bit of force required to cause ONE rear tire to turn if both are off the ground and the transmission is in park.Cody/QUOTE]



.. ....my way is more fun.

 

I agree completely

 

annnnnnnd.... if it's a clutch style LS, the clutches need to be warm...

 

I'd like to cast a vote for just wheel it and see if both tires spin.

 

I'ver heard with the ls in some of the new superduty's that to get the ls to really work how it's supposed is to setting the parking brake lightly.

 

I'm all for finding a nice safe straight spot of road and stomping it then checking for two nice black stripes. If there's only one you are not geting enough torque transfer( No LS, worn out LS clutches, factory LS too wimpy, etc) Why road? Road is a more severe test than grass. You need more torque transfer to spin both tires, due to higher friction.
They are absolutely right, there's an actual procedure to test your LS. However stomping it is easier and faster.

 

sounds great guys. I stomped it today and there were two black tires streaks, so I guess it's working.

But, for some reason, I thought that if you do that in a car or truck with 2wd in the front or rear, if you peel out, then it still leaves two marks??

 

on a surface that is level side to side, most of the time a vehicle will leave 2 marks due to the fact that the friction coefficient is equal on both tires.. get one tire so the coefficient is higher than the other- maybe one in the ditch?- and then see what happens...

 

There's a bias toward the right wheel due to differential design if I remember right. You see it at drag strips on street night when open differential cars do a burn out.
You can do fordraceboy's test if you want to, but if it's leaving two stripes what more can you gain?

 

Want to know why?

Looking from the rear of the vehicle, the engine crankshaft (and ultimately) the driveshaft will be spinning in a counter-clockwise direction. When torque is applied to the driveshaft and pinion gear in the axle, a couple of things happen.

1. The pinion gear attempts to "climb" the ring gear. It's easier for the suspension components to flex a little bit than for the tires to push a 1.5-4 ton vehicle. This is why the pinion end of the axle housing tries to rotate upward under acceleration.

2. Again, since there is resistance to vehicle movement, the counter-clockwise rotation of the driveshaft (engine torque) actually tries to LIFT the right rear wheel off of the ground. The suspension on the right side is being compressed......not because of weight transfer but because of the engine torque trying to rotate the entire rear axle counter-clockwise (when viewed from the rear).

That's why dedicated drag-racing vehicles use a link-type suspension for EFFICIENT launches. Instead of torque being wasted and absorbed by soft suspension components, the links will transfer nearly all of the torque to the frame of the car........making it quicker to respond. In addition, think of why lift blocks under leaf springs cause such issues under acceleration.

Cody