Limited slip differential, is it worth it?

[David Muench]

The only mistake I made when I ordered my truck was not ordering a LSD. I figured there would be lockers available soon enough. I was wrong, here I am 2 years later with zilch. .

 

[RMontoya]

I opted for 2WD w/ limited slip, instead of 4WD. I've had three 4WD trucks over the years and rarely used 4WD. My driveway is 125 feet long and uphill (both ways). I have not had a problem getting in or out in the snow.

Now I need to find a piece of wood to knock before the weather turns.

 

[randyn]

When I first got my truck (03) I stopped on side of road w/ one side of truck in the dirt/gravel, and the other side on the pavement. In 2 wheel drive, I stomped the go pedal and got a black streak of rubber on the pavement. The dirt side tire spun also, but that black streak really impressed me.



RandyN

 

[CRumsey]

I'm glad that there are so many here who are happy with this LSD; but my experience has been a little different. This past winter if all I would've had was the LSD I would have been stuck on several different occasions. I was really glad I had purchased the 4 X 4 because it was what got the truck going when the LSD did not function. As previously mentioned this is a torque differentiating differential. Meaning both sides need to be on something that will create traction of some sort to turn both wheels. My experience was, and this is a fact, with the left side sitting on dry salted pavement and the right side setting on ice or snow; the right side on the ice would spin and spin while the side on the pavement sat there and took a coffee break. I had to switch into 4 wheel drive to move the truck and it happened more than once. My feelings are that this is a severe limitation in the capability of this differential. It was such a problem that I took it in and complained that the LSD was not functioning; the dealership said it was functioning as designed.

 

[MBigelow]

Intermittent LSD?

Sounds like some are seeing a big difference with the LSD applying the power to the wheel on the pavement as it should, while others just sit and spin the wheel with the least amount of traction.



Wonder if all LSD's are created equal?



Mel

 

[XJSuperman]

CRumsey... I would have expected this and any 'anti-spin' or 'limited slip' differential to behave just as yours did on the ice. Only a 'locking differential' or spool would have made both wheels pull. When enough pressure is applied to one wheel of an LSD or anti-spin diff... it will act as an open diff... . OR if one wheel has significantly LESS traction than the other which is what your case is/was... it will act exactly as it did. Basically if you had one rear wheel off the groudn and one on the ground... the one in the air would spin. With any lsd or antispiin... yes... it is significantly better than an open diff... BUT you still need somewhat ideal conditions. Hence the name "anti-spin" and not "locking differential"... I apologize for sounding like a smart-alec... if I do I'm not meaning to do so.

 

[NSperduto]

I'm glad that there are so many here who are happy with this LSD; but my experience has been a little different. This past winter if all I would've had was the LSD I would have been stuck on several different occasions. I was really glad I had purchased the 4 X 4 because it was what got the truck going when the LSD did not function. As previously mentioned this is a torque differentiating differential. Meaning both sides need to be on something that will create traction of some sort to turn both wheels. My experience was, and this is a fact, with the left side sitting on dry salted pavement and the right side setting on ice or snow; the right side on the ice would spin and spin while the side on the pavement sat there and took a coffee break. I had to switch into 4 wheel drive to move the truck and it happened more than once. My feelings are that this is a severe limitation in the capability of this differential. It was such a problem that I took it in and complained that the LSD was not functioning; the dealership said it was functioning as designed.

I'm with Crumsey, I think the rear is a piece of crap for the exact same reason he states. Given that you have 4X4 I think it's a waste of money.



When I get in slippery situations, I never know if the rear is going to grab or not, so I always put it in 4X4 when on the lawn, etc.

 

[NSperduto]

CRumsey... I would have expected this and any 'anti-spin' or 'limited slip' differential to behave just as yours did on the ice. Only a 'locking differential' or spool would have made both wheels pull. When enough pressure is applied to one wheel of an LSD or anti-spin diff... it will act as an open diff... . OR if one wheel has significantly LESS traction than the other which is what your case is/was... it will act exactly as it did. Basically if you had one rear wheel off the groudn and one on the ground... the one in the air would spin. With any lsd or antispiin... yes... it is significantly better than an open diff... BUT you still need somewhat ideal conditions. Hence the name "anti-spin" and not "locking differential"... I apologize for sounding like a smart-alec... if I do I'm not meaning to do so.

Riddle me this one, then. I have a 98 Dakota that was equipped with antispin or LSD or whatever you want to call it. I can put one wheel on the ice and the other on the pavement and they both spin at the same time and away I go. I get absolutley zero spin out of the wheel on the ice.



I pull up to this same exact spot with the ram and I sit there stuck in 2wd.



I know this for a fact because I still own both trucks and I go to one specific corner all winter that always has ice and snow on the side of it at the stop sign where I need to stop, check traffic on the highway and pull out. I step on the ram pedal and away she spins. I step on the dakota pedal and I zip out onto the highway.



Maybe you guys who love the LSD in the RAM never drove a truck with a real posi unit. Or suregrip as the older mopars used to call it.



Nick

 

[XJSuperman]

Riddle me this one, then. I have a 98 Dakota that was equipped with antispin or LSD or whatever you want to call it. I can put one wheel on the ice and the other on the pavement and they both spin at the same time and away I go. I get absolutley zero spin out of the wheel on the ice.



I pull up to this same exact spot with the ram and I sit there stuck in 2wd.



I know this for a fact because I still own both trucks and I go to one specific corner all winter that always has ice and snow on the side of it at the stop sign where I need to stop, check traffic on the highway and pull out. I step on the ram pedal and away she spins. I step on the dakota pedal and I zip out onto the highway.



Maybe you guys who love the LSD in the RAM never drove a truck with a real posi unit. Or suregrip as the older mopars used to call it.



Nick

No riddle to it... your dodge dakota most likely had the 'trac-loc' differential. . in either the 8. 25 or 9. 25 chryco corp axle right? This is a clutch designed LS and many times they are VERY tight and will act more like a locker... but after enough mileage you'll eventually wear out the clutches and have an open diff.

ALSO...comparing a ~4000 lb dakota to a 7,000+ lb ram is no comparison. My dakota was the same... yeah... I owned a '98 also with the LS. There's virtually NO weight over the rear of a dakota... so even one on ice and one on hard ground you have a much better shot of it moving than the ram as the ram puts MUCH more weight over the rear even when empty than the dakota... thus you get enough pressure on the wheel on hard ground to make it stand still and the other spin.

I've driven posi, locekrs, and spools both on and off road for over 10 years now... and I'll grant you the same axle in the same truck will behave differently all things being equal. Meaning if you put our trucks side by side one they will behave slightly different in similar situations... (IE your "anti-spin" may not be as tight as mine or someone elses). but I can assure you these units do exactly as they should even in the ice situations you described.

 

[NSperduto]

but after enough mileage you'll eventually wear out the clutches and have an open diff.

Ok. but I wonder what "enough" miles are.

I have 168k on it now and it still performs like new.



When I think of LSD, I thnk of Posi-traction, when I think of posi-traction, I want a vehicle that when I stomp on the gas, I'll see two tire squealing and rubber burning and two black strips right up the street.



I'm not trying to argue with you, I just think the lsd blows.



Nick

 

[XJSuperman]

I don;t think you're arguing... and I do see your point... BUT even a posi traction unit is NOT the same as a LOCKER or SPOOL. It too has limitations.



You are lucky that in 168,000 miles your dakota's LSD is still functiong the way you describe... if it is the 'trac-loc' most don;t last that long... BUT if your truck is not in a situation where the LS is actually being used... then it will last longer.



The reasons I think the 'anti-spin' in our rams is better are easy: #1) It's gear driven... there are no parts to wear out ever. So unless you actually break it it will last indefinitely. #2) There is NO special lube needed... just use whatever the gear lube specified for the AAM axle (which is VERY common). In my ram... this performs as well if not better than the trac-locs I had in the 2 jeeps I had with them AND my dakota.



Again I am not arguing with you BUT I still hammer the point that this is NOT in any way a locking differential such as a "detroit locker" or a spool. It IS indeed a LIMITED SLIP... even if DC or AAM calls it an "anti-spin". It just simply will not function as a locker when enough pressure/weight is put over one tire vs the other... period. That's why most of us are happy is because it does what it should... maybe not what we'd LIKE it to do... but it does what it should.

 

[JHardwick]

whew, talk about the long way around the mulberry bush!



A limited slip rear is just that ... ... ... ... . "limited slip". <~~read that



On edit you won't ever get power to both wheels with an open rear!



Man, I off roaded for many years, mostly back when a dollar was hard to come by. Most generally the LSD in the Dana was decent, but you get one wheel off the ground and it's time to lock 'er in. You really had to be on the hammer to keep both rears powered. Yeah, we were all about who could make it the farthest down the trail in 2wd.



Back then we opted for the Lincoln Locker Oo.

 

[XJSuperman]

whew, talk about the long way around the mulberry bush!

I know I was long winded... but I;ve made this same point in MANY other posts and there's always someone who thinks this thing should lock up like an actual locker when it indeed should not.

 

[rbattelle]

#1) It's gear driven... there are no parts to wear out ever. So unless you actually break it it will last indefinitely.

This isn't true... there are pinion brake shoes that will eventually wear out. Remember that the torque bias is created by the coefficient of friction between the end face of the side gears and the differential housing. You cannot construct a limited slip mechanism without friction.



Hey 03whiteram, check out this thread , Gypsyman says he got an LS center section from Randy's for $517 (about 1/2 way down the thread).



I have mixed opinions on the LSD in these axles. I think it's better than an open diff, but could have been better designed for more torque biasing (this could be achieved by increasing the helix angle on the side gears). A torsen-type differential may be designed with bias ratios ranging from about 2. 5 to 6 (an open type differential is capable of about 2:1 bias ratio at best). Ours is most certainly at the low end of that range, probably to emphasize tire longevity rather than torque biasing capability.



Most importantly, this is a torque multiplier: the product of anything and zero is zero, so if one wheel is on ice and the other is on pavement, there isn't enough torque to transfer to the "good" wheel to make this heavy truck move (this also explains why jacking up the rear and spinning one wheel causes the other wheel to rotate as if it were an open type differential).

 

[JPereira]

I had bought my 4. 5 Ram last spring. I did order the truck with the limited slip. I recently changed the fluids in both front and rear and was surprised to see the front does not have the same LSD like the rear does? The is my first 4x4 so I did not know if this is normal? Does that mean only 1 tire is actually pulling up front when in 4x4? Is the front what they call a standard Open Diff?



Jeff

 

[rbattelle]

I had bought my 4. 5 Ram last spring. I did order the truck with the limited slip. I recently changed the fluids in both front and rear and was surprised to see the front does not have the same LSD like the rear does? The is my first 4x4 so I did not know if this is normal? Does that mean only 1 tire is actually pulling up front when in 4x4? Is the front what they call a standard Open Diff?



Jeff

This is completely normal. There are very few vehicles out there that come from the factory with a limited slip front end. I think Jeep Grand Cherokee's with the Quadra-Drive do, and I think the new Dodge Power wagon does, and probably some high-end stuff like Land Rover might, but they are the exceptions. The front, then, is a normal "open" type differential.



With luck, one of the aftermarket lockers will become available for our axles.



-Ryan

 

[DPelletier]

This is completely normal. There are very few vehicles out there that come from the factory with a limited slip front end. I think Jeep Grand Cherokee's with the Quadra-Drive do, and I think the new Dodge Power wagon does, and probably some high-end stuff like Land Rover might, but they are the exceptions. The front, then, is a normal "open" type differential.



With luck, one of the aftermarket lockers will become available for our axles.



-Ryan

Yep, completely normal, like Ryan has stated. If you want something with front and rear lockers get the Jeep TJ Rubicon with F and R air lockers.



I'm in the "get the LSD" crowd. It may not be perfect, but what do you save by not ordering it? The option's MSRP on my '03 was $395. 00, so I probably paid about $300. 00 Canadian pesos! Not much on a truck that had an MSRP of $53,160. 00



Dave

 

[DocDetonancour]

I'm glad that there are so many here who are happy with this LSD; but my experience has been a little different. This past winter if all I would've had was the LSD I would have been stuck on several different occasions. I was really glad I had purchased the 4 X 4 because it was what got the truck going when the LSD did not function. As previously mentioned this is a torque differentiating differential. Meaning both sides need to be on something that will create traction of some sort to turn both wheels. My experience was, and this is a fact, with the left side sitting on dry salted pavement and the right side setting on ice or snow; the right side on the ice would spin and spin while the side on the pavement sat there and took a coffee break. I had to switch into 4 wheel drive to move the truck and it happened more than once. My feelings are that this is a severe limitation in the capability of this differential. It was such a problem that I took it in and complained that the LSD was not functioning; the dealership said it was functioning as designed.

Ditto. Snow on one tire = my Miata will do better than the LSD. Doc

 

[E7mack96]

my $. 02,



The limited slip in my '03 ram works great. maybe too good. It breaks one set loose on almost all turns. in the rain, it can get scary in a turn.



My rear tires are almost bald at 40,000 miles, but the fronts look great.



I attribute this to the rear limited slip spinning one set in the turns.



I have owned 3 of these Rams and all 3 had tight "posi" rears.

 

[Crunch]

Oh yeah, it has to be the LSD...

my $. 02,



The limited slip in my '03 ram works great. maybe too good. It breaks one set loose on almost all turns. in the rain, it can get scary in a turn.



My rear tires are almost bald at 40,000 miles, but the fronts look great.



I attribute this to the rear limited slip spinning one set in the turns.

I attribute this to stomping the pedal on the right as you enter the turns. :-laf



I've got just under 37K on my original tires (Michs). While they show significant wear, I bet I can get another 10K miles out of them. I also have a question for the anti-LSD folks: My truck will also get stuck in wet grass or in mud, but I've never attributed this to the LSD. The few times it has happened I wished I had gotten the 4X4, but it may not even be that. To what extent could your no-traction experience be caused by the tires that are on your truck, and not anything to do with the axle?