I'm not the limited-slip differential in my trucking is working. This past weekend I was scouting out a place to hunt and crossed a dry creek bottom. As I drove out of the creek bottom, the right rear wheel kept spinning. The third time up, the truck came out without spinning. I did move over a little to avoid a rock that one of the front wheels was hitting.

How does the limited-slip work? My truck has a C1 (3.73 limited slip) axle. I have heard that it will allow one wheel to spin about a quarter round and then engage the other wheel, thus allowing one wheel to spin faster than the other in turns but providing extra traction if one wheel loses traction.

 

The Limited slip works after one wheel turns faster than the other in about 1/4 turn this engages the clutch plates to lock the axels .Now I hope you have some what of an idea on how it works ,but it also needs service and when you do this you must put friction modifier with a synthetic gear lube

 

Here's a fairly good explanation:
http://auto.howstuffworks.com/differential8.htm

 

Other than chaining the truck to a BIG tree and trying to pull it up, how can I test the L/S to make sure it is working?

 

These LS are not the best units on the market. I have found that it takes a few RPM's from the engine to get the LS "kicked in".

Did you give the tires a good spin when you were stuck or did you just give it enough throttle to try to get moving?

 

the ford factory LS is not a very agressive unit, and it takes a good amount of torque to lock it up, for instance, if you have one tire on snow or ice and the other on dry ground and hit the gas the tire on the snow will just spin and the other tire will not provide any additional traction because the tire that is slipping is to putting enough torque into the LS to lock it up. to get the truck moving in a situation like this you have to apply the parking brake little by little to increase the torque on the LS to get it lock, then you will move. if you want to see if your LS is working, do a power stand and smoke your rear tires a little, if there are 2 black marks then its working(both tires on dry pavement creates enough torque for the unit to lock up)
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Did you give the tires a good spin when you were stuck or did you just give it enough throttle to try to get moving?[/QUOTE]

Yes. The right rear tire was spinning on a rock. It spun enough to create smoke.

 

[QUOTE=wlihntr]the ford factory LS is not a very agressive unit, and it takes a good amount of torque to lock it up, for instance, if you have one tire on snow or ice and the other on dry ground and hit the gas the tire on the snow will just spin and the other tire will not provide any additional traction because the tire that is slipping is to putting enough torque into the LS to lock it up. to get the truck moving in a situation like this you have to apply the parking brake little by little to increase the torque on the LS to get it lock, then you will move. if you want to see if your LS is working, do a power stand and smoke your rear tires a little, if there are 2 black marks then its working(both tires on dry pavement creates enough torque for the unit to lock up)
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So, if I understand you correctly, if one wheel is spinning, say up in the air or on ice, there isn't enough torque between the two wheels to lock in the wheel that's on good ground. Both wheels have to have some traction on the ground in order for the LS to work. If one wheel completely breaks traaction, it will just spin while the other tire just sits there.

 

yep, you got it. the tire with the loss of traction has to put a certain amount of torque into the LS to activate it. if it doesnt then it will act just like an open diff. thats why the parking brake trick will work

 

Just as a side note, before you go into the "why did Ford give me this junk LS rear-end", remember that 99% of what automakers do on these trucks is so the biggest idiot on planet Earth can drive them, and if they did happen to put an aggressive LS in, imagine the deluge of people bringing their trucks into service because "It chirps when I turn!"... My wife constantly complains about the vanilla stuff they put in cars nowadays so the soccer moms can drive them all...

 

the only thing keeping one wheel from spinning faster than the other is a pack of clutches (like a motorcycle clutch) when one wheel gets broke free you need to stop spinning it and let the clutch pack tighten itself up and then pull up slowly and straight if you spin that one wheel enough you will wear out those clutches, if it is a ford limited slip

 

I put an Auburn LS in my '96 t-bird, and I was able to remove both rear tires when BOTH were in the air, meaning the break-away torque of the unit exceeded at least 150 ft/lbs. However, in really slippery conditions and a lot of gas, it was still possible to break loose the Auburn limited-slip.

The stock Ford Traction-Lok is supposed to be "good" at 25 ft/lbs. Not sure if that applies to the Sterling 10.5" or the Dana 80, but I know the Dana 60 Traction-Lok in my '74 stinks no matter what I do. It's still "Traction-Lok".

And yeah, I agree, the accidents caused by a "good" limited-slip would be enough to put Ford out of business. My t-bird with the Auburn was a sled on ice/snow/rain, but very fun to drive. It was also nice to be able to blast the gas from a corner and pull out into traffic without worrying about tire spin (too much)... as long as you didn't hit it TOO hard because you'd spin it right around without too much effort.

I plan on going with an Auburn when I buy out my '01 F250 lease in 2 years

 

Find a dirt road punch it and check to see if both rear tires are spinning or just one.