what he said...

regardless, what osteo said about having to be moving is way off base... if you punch it from a start with a LSD you should leave two black marks... with an open diff you leave just one. An LSD is only supposed to act like an open diff when you are turning.

 

You are right about not being in motion. I reread my post and now I wonder what I was thinking that night. Oh well. Brain Fart

As far as the LSD I'm a little confused. So what you are telling me is that LSD is a locker? That one wheel doesn't have to be moving for the LSD to work and that they are locked all the time unless you are turning? I thought they worked based on friction and that there had to be a big enough difference in wheel speed to make it lock making it a LIMITED SLIP?

If I am wrong, I do want to know because I don't want to give out ill guided advise.

I have used the braking method to regain traction in otherwise tricky situations. It slows down the spinning wheel enough to get some traction and allow the vehicle to move enough to get better traction. Kinda hard to explain. Anyone that does enough wheeling understands that you drive as slow as possible and as fast as necessary.

 

Here goes nothing...

By default all differentials try to divide torque equally to both wheels. If one wheel is on a slippery surface or in the air, then it takes little or not torque to make it spin... so little or no torque is applied to the other wheel, so that wheel does not move and the other wheel spins like crazy...

LSD are set up similar except that they have clutches in them to artificialy create friction from one side of the rear end to the other. If both sides are trying to spin at the same speed the clutches just stay locked and there is no problem.

If one side tries to spin faster than the other it has to first overcome the friction created by the clutches. Once it does one wheel can spin faster than the other. To do this generally requires the high friction of a modern tire against a dryish paved surface in a turn. If the amount of force required to break one tire loose is greater than the amount of force required to get the clutch to slip a LSD behave just like an open dif (an example would be to put a really knobby tire on one wheel and a bald tire on the other and do some extreme mudding... once the knobby tire gets stuck the other tire will just spin... this is why hardcore off roaders will often prefer true lockers... no clutches to wear out, so greater durability, and no chance of getting stuck because of a really extreme difference in friction between the rear tires.). Generally the amount of friction on both rear tires is aproximately equal, so bothtires spin at the same speed.

Friction modifier is added to the rear end to reduce the clutches efficiency. The more you add the less well they work. If you add to much your rear end acts just like an open one. If you add to little the clutches do not want to let go and your rear end stays locked.

The fact that this setup acts like a locker can be demonstrated as follows (BTW: DO NOT DO THIS)...

Drain your LSD equipped rear end.

Refill with correct fluid

Do not add fricition modifier.

Go driving.

Your truck will act like it has a badly installed locker... jumping rattling and lots of driveline chatter... the reason for this is the clutch packs not releasing.

I have first hand experience of this because the guys at the chrysler hose did not put in FM when they rebuilt my axle's internals (y'all may remember the incident with the snapped half shaft). I cannot blame them for this, as my truck is labeled as having an open dif and if they decoded the VIN I am sure that the computer told them not to use it.

I picked up my truck on friday night, noticede the symptoms, took it back on monday and they drained the fluid again added the friction modifier and the limited slip is almost unnoticable unless I am gasing it or acting irresponsibly on a slippery surface.

Another, possibly safer, method is to jack your rear end up put the truck in neutral and turn one of your rear wheels.... lockers and LSD will ause the other wheel to turn in the same direction. Open diffs will either not move the other wheel or it will rotate in the opposite direction.

BTW

1)Anti-spin is kind of a deceptive description. Open differentials are way more forgiving on slippery surfaces once you are moving... Anti spins are better to get you moving (in all conditions... be it dry surface with a really heavy trailer or snow whilst unladen)

2)Using your brakes as osteo recomended is a great method to help with an open diff or a LSD which is acting up or has too much FM... you are increasing the amount of torque sent to both rear wheels by increasing the friction on them. It is the percentage difference in load on the wheels that causes one tire to spin. If you can make the driveline work to overpower your brakes, instead of break your tires free, you are essentially doing what a LSD does internally.

3)When trying to go forward your right wheel tends to spin... when backwards your left... this is because when you are going forward your entire driveline tends to spin clockwise (when viewed from behind) attempting to lift your right wheel off the ground... when you are going backwards the opposite is true... this causes one tire to have better traction than the other. Of course if one wheel is not on the ground or on ice this minor variation is overwritten.

 

Consider me educated on the operation of LSD. Thank you Frogslinger. By the way, interesting screen name.

 

If you want to know the correct way a diff works just visit this site, it should explain a little better http://auto.howstuffworks.com/differential.htm

 

hey guys,
i have an 04.5 diesel now, but i had a 2000 2500 4x4 with the anti-spin. before i hit 20k miles i had to have new clutch packs in the rear end. my problem was that the rear would not unlock and every time i turned i was getting the dreaded chatter. you can try driving real slow with a buddy walking beside you and as you turn he will hear the chatter if your packs are bad. from what i have read, if you do a lot of burnouts and tire spinning, these factory clutch packs will not hold up. jjust my experience- hope it helps.

 

I had a 94 ranger 4x4 and I put a lockrite in the front and a Powertrax no slip in the rear and let me tell you even with 4.56 gears and 35's that thing never failed me. if my 3.92 LSD goes out in my 03 QC 4x4 I'll consider putting one of those in, but I am not offroading my Ram so I might go with an auburn LSD Don't know.

 

thanks for all thr advice, i brought my truck in and dodge said there is nothing wrong and they drained and checked my rear diff and now its fine i tried the one side on ice and other on pavement and off i went i dont know what they did but its fine now. maybe the fluid was low i dont know all i care is that its all fixed!!! thanks again

 

just figured out i have 3.55s and an open rear.... might aswell have a v6 then

 

I wanna know how this turns out as well. I have an '06 QC 2x4 and the truck was supposed to have the LSD when I bought it, figured out that it didn't, the dealer put it in, however, I still only spin one wheel. I got stuck on a hill in the RAIN. I've been thinking about a locker as well. Have another post asking for traction and handlingset upsand tips.