L.S.D doesn't work Ram 1500

[cbsmith]

I have a 2014 Outdoorsman with 3.92s and a LSD. I was on the side of a road a couple weeks ago and had the drivers back wheel on pavement and the passengers on the gravel shoulder. I accelerated from a stop a bit too quickly and the truck spin until. The traction control kicked in. When I looked back there was a black mark on the pavement that matched perfectly with the rut in the shoulder the other tire made. In my previous truck with an open diff the only spinning tire would have been the one in the gravel.

 

[Ricks Ram]

Was it your drivers side tire or passenger side tire that was on the pavement?

 

[Ricks Ram]

For those who don't know, the Dodge Anti-Spin LS is different then traditional LS carriers. Unlike normal LS which has constant pressure on the clutches to keep the axles turning at the same speed the Anti-spin is a non pre load design meaning the rear end will act like an open rear diff when it does not sense torque on the gears. This design makes it more fuel efficient when doing basic city or highway driving.

When differential torque is applied to the gears it applies an axial counterforce on the clutch system to get the torque bias equaled to the axles. So when the torque input is very low the force needed to counter the torque bias will be decreased so you get the results of an open differential.

If you were to spin the tires in the air under normal condition it will appear to be an open diff.

So when you try to burn out on 2 different surfaces of unequal tractions, its gonna spin like an open diff. The system is designed to be used with the traction control and ABS because if you drove lots of regular LSD trucks, you know that they can have a nasty habit of getting away on you on slick surfaces like ice or wet pavement.

In other words in only works as an LSD when its actually needed.

Thanks for the information that is pretty much what I am figuring out with the research I have been doing. I jacked up the truck and you are right it just free wheels like an open diff. My biggest complaint with this is that this WAS in a situation where it was needed and I feel should have worked. Both tires were on good surfaces. I would think it would have had enough traction to activate. It's not like it was just free wheeling I was on a hard driveway going uphill turning right. The drivers tire was on pavement the passenger tire was on compacted road base like gravel. The passenger front tire was up against about a one foot high berm. The passenger rear tire started to spin. It had enough traction to bounce the rear of my truck up and down when the tire was spinning. I wish I would have taken a picture of where it happened. In any case I will look at it Wed at the dealer. I mainly what to see if another truck on the lot with L.S.D acts like mine. If it does I guess I'm stuck with it until they make something better.

 

[cbsmith]

Was it your drivers side tire or passenger side tire that was on the pavement?

Drivers side on pavement, passenger side on the gravel.

 

[Ricks Ram]

Thx after I spun in the driveway I did exactly the same thing to see what what would happen and I only spun one tire. It seemed like it worked better if I put the passenger side on the pavement and drivers side in the gravel. Not sure why.

 

[Ricks Ram]

Okay I will try to make this as short as possible. I dropped my truck off this morning with the dealer. I took the Technician for a test drive and showed him what the truck was doing. I deliberately showed him how if the right tire was in gravel and the left tire was on pavement it would only spin the tire in the gravel. He explained to me that it was a limited slip and not a positraction. I said ok then I guess it won't work on the other side either let's see. I put the left tire in the gravel and the right tire on pavement and it worked perfectly and spun both tires. He was obviously surprised and said they would look into it. When back to pick it up 7 hrs later and they handed me a printout of how it's supposed to work directly from Chrysler and said it was fine and it was working correctly. It clearly states in the printout THEY gave me that the power would be transferred to the wheel with traction and mine clearly doesn't do that. I guess they just thought that I wouldn't understand what it said. I told the tech that's a bunch of B.S. I paid for limited slip and for some reason it only senses torque on one side. I could tell he agreed with me but was stuck in the middle. I went into the service manager and told him I wanted an explanation for there decision. After going back and forth and me pretty much shooting down every stupid explanation he agreed to test another truck with L.S.D and it worked perfectly on both sides and spun both tires equally much to there surprise . They opened a Star case to investigate I told them I didn't really care what anyone said I wanted it replaced. The Technician agreed with me and said somehow my rear end only senses torque load or works on the one side. I have no idea why or how. I know this is far from over but I am hoping we are going the right direction. I had another friend check his with a 3:92 L.S.D and he said it spun both tires as well. I wasn't there to see it but I trust his information. I just want to get it fixed so I have what I paid for. So that's it for now. I was very impressed by how well the other truck's L.S.D. worked hopefully this will all get worked out.

 

[ram_tech]

weird... most plases probably would have just quoted you a rebuild or replacement unit and been dont with it. and isnt this your 2014? rear axles are part of powertrain warranty 100k but not sure if the LSD is considered a wear item or not kinda like a clutch disk they have shorter waranty limits.

dont understand why they would fight it pretty simple. and if you ever hear some one say its limited slip not a posi please please please never get your car fixed by that persion. its like saying its not abs just anti lock brakes.

 

[Ricks Ram]

Yea it's under Warranty. It only has 7800 miles on it. I am not sure why they are resisting a little. The Tech agreed with me and said it has some type of a problem. It's the service manager who said they need more info and wanted to open a Star Case. It doesn't matter I won't stop until they fix it.

 

[loveracing1988]

weird... most plases probably would have just quoted you a rebuild or replacement unit and been dont with it. and isnt this your 2014? rear axles are part of powertrain warranty 100k but not sure if the LSD is considered a wear item or not kinda like a clutch disk they have shorter waranty limits.

dont understand why they would fight it pretty simple. and if you ever hear some one say its limited slip not a posi please please please never get your car fixed by that persion. its like saying its not abs just anti lock brakes.

Easy to explain, warranty pays less than customer pay. The same reason I have had the same fight with a spoiler rattle every single year on my wife's jeep. Every summer they re-torque it and after a winter it comes back the next summer yet I was told "nothing is broken so there is nothing else we can do".

 

[TRCM]

Sounds like when GM told me the g80 locker wasn't designed to work in reverse.......

and as for the limited slip vs posi-traction thing.....it like a coke vs a pepsi...same basic thing, only real differences is whose brand name is on it.

 

[Ricks Ram]

In the Tech ' s defense I think he was referring to a locking differential when he said it wasn't Positraction. As soon as he saw what I was talking about he never wavered from the fact that it wasn't working correctly. It's the Service Manager who is doing all of the side stepping. The more I think about it the more pissed I get. I can't stand people trying to B.S. me. If I wouldn't have known about cars and mechanics in general I would have totally bought what he was saying. I am going to try and be patient (not one of my virtues) and give them a few days. If I don't hear from them then they will hear from me. I just want what I payed for.

 

[Ricks Ram]

Finally heard from the dealer today. I was told that they talked to Chrysler tech support and they suggested that they replace my differential. They said they will order it and let me know when it comes in. I hope this one works correctly. I am glad they decided to just replace it so I can get it fixed and be done with it. Not sure if mine was a fluke but if you have the Chrysler Anti Spin diff in your 1500 you might want to check and make sure it is actually working when you wheels don't have equal traction like it's supposed too.

 

[7777xm]

Yeah, yours seems broken. Mine locks no issues on two surfaces, usually pavement/grass.

Glad to hear they are replacing it.

Sent from my SM-N915T using Tapatalk 2

 

[Tach_tech]

There is actually a measurement that can be done on the side gears. The measurement is taken from the distance between the two side gears. If it's above spec, the carrier is supposed to be replaced.

 

[loveracing1988]

There is actually a measurement that can be done on the side gears. The measurement is taken from the distance between the two side gears. If it's above spec, the carrier is supposed to be replaced.

Diff gear backlash? If so I'm willing to bet that the tech finds what the spec is, adds some and says that is what it is to get a new diff case ordered.

 

[Tach_tech]

Diff gear backlash? If so I'm willing to bet that the tech finds what the spec is, adds some and says that is what it is to get a new diff case ordered.

No, not backlash. Differential backlash is measured between the ring gear and pinion gear, which has no effect on the LSD portion. This spec is to measure the distance between the two differential side gears, 1.66" is the max. If it's above its likely there is excessive wear on the clutches,side gears,case etc.

 

[loveracing1988]

No, not backlash. Differential backlash is measured between the ring gear and pinion gear, which has no effect on the LSD portion. This spec is to measure the distance between the two differential side gears, 1.66" is the max. If it's above its likely there is excessive wear on the clutches,side gears,case etc.

No, I am referring to differential gear backlash, lock one side out and measure the total lash between the side gears and pin gears. We take that measurement at work on certain tests.

 

[Tach_tech]

No, I am referring to differential gear backlash, lock one side out and measure the total lash between the side gears and pin gears. We take that measurement at work on certain tests.

Oh ok, ya no that's not the measurement they want done. As far as I know Chrysler doesn't even list a spec for side/pinion gear backlash. I pulled the picture out of the service procedure showing where the measurement is taken.

 

[loveracing1988]

Oh ok, ya no that's not the measurement they want done. As far as I know Chrysler doesn't even list a spec for side/pinion gear backlash. I pulled the picture out of the service procedure showing where the measurement is taken.

That seems much easier than guessing how to read diff gear backlash. Although I would guess a normal caliper would be a pain to get in there.

 

[Tach_tech]

That seems much easier than guessing how to read diff gear backlash. Although I would guess a normal caliper would be a pain to get in there.

Ya it would be a pain with calipers, be best to use a telescopic gauge.