Is my Limited Slip Differential Working?

[Explorer_Phil]

I have had my '01 Sport for a year and a half now and have taken it off roading many times, it's great. The previous owner (it was a fleet vehicle) ran this thing into the ground, so I've been fixing it up since I bought it.

While offroading, I thought how nice it would be to have a Limited Slip Differential on my explorer. With a little research, I discovered that I in fact DO have a LSD on my explorer. This confused me, becasue I'm pretty sure that I have never heard it kick in. Other vehicles I've been in with LSDs were loud and made the tires squeek around corners...which has never happened to me. So I'm at a loss.

I'm wondering if there is a reliable test that I can do to see if my LSD is working properly, or if I need to replace some parts inside. Thanks.

 

[KPT]

You are thinking of a locker. LSD'd won't chirp a tire in a turn.

Get your rear axle on jackstands. Turn a tire. If the other tire turns the same direction the LSD is working.

 

[patman]

i knew mine worked when one tire spun cuz it was on ice and the other tire stood still for a while but i felt it kick in when i started moving

 

[dmac0923]

You are thinking of a locker. LSD'd won't chirp a tire in a turn.

Get your rear axle on jackstands. Turn a tire. If the other tire turns the same direction the LSD is working.

This way is the more accurate way to determine if your truck has a working LSD.

If your on ice/snow/mud and you get the rear wheels spinning fast enough you can get both rear tires to spin from the centrifugal force.

i had a jeep wrangler that i was unsure if i had a LSD or not. i tried the snow/ice method and both tires spun.....jacked the rear end off the ground and the tires spun opposite directions----NO LSD. ran the axle code to verify and indeed no LSD

 

[Crunchy]

Or the proper way to test your l/s as explained in the ford service manuals:

-chock front tires
-tranny in neutral
-jack one rear tire off the ground
-put a torque wrench on one lug nut of your lifted tire

Now determine the torque needed to start turning the tire. Ideally you want a special tool so that your torque wrench is centered at the axis of rotation for the tire, but not really needed.

If the torque is in the mid to upper twenties ft-lb, then your l/s is OK as per factory specs.

If its less then you l/s is getting worn down, time to invest in a rebuild kit from your local dealer.

Or the redneck way of doing it: jack up one rear tire, put it in gear and give 'er gas. If you move, your l/s is ok, if your still on the jack, your l/s is shot.

 

[Turdle]

If it will leave 2 black marks when powerbraking, and does not chatter during sharp turns, it is working

 

[99SportX]

If it will leave 2 black marks when powerbraking, and does not chatter during sharp turns, it is working

I can't wait to really try out mine once the snow hits. It should be a different drifting experience compared to the open diff I had last winter.

 

[wingnutt550]

I have a simmlar question. 1996 explorer 4x4 with an axle code of 45. At the beach in two wheel drive both rear tires will dig in until the rear is burried. According to all the charts I have seen I have a 3:55 open rear end. Any one know why? Due to the lack of service on every thing else i don't think the previous owner up graded it. And why would a 4x4 be shipped with an open rear end. may be the drivers door was replaced with a junk yard special? any suggestions.

thanks, Steve Z.

 

[KPT]

At the beach in two wheel drive both rear tires will dig in until the rear is burried.

That is normal. I know my rear is open and it will do the same thing in sand.

And why would a 4x4 be shipped with an open rear end.

The vast majority of ALL manufacturer's 4x4s are open front and rear.

 

[Cobraguy]

I know of no LS front end being supplied from the factory any longer. I think Ford stopped in the late 60's, early 70's. Good way to end up dead.

A conventional, non posi rear diff can actually leave two black marks or spin in mud, etc. As long as traction is equal to both wheels, both will spin. When traction gets the least bit different between the two, the one with the least bite will spin.