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I am 99% convinced the car I a looking at doesn't have the LSD based on the datacard. However, just to be sure, is there a noticeable difference visually between the LSD and open diff? I mean when installed, of course. Can I crawl under and verify for myself? Does anyone have a pic of the LSD taken from underneath the car?
I understand some US-spec cars seem to have come with the cooling fins on cars w/ open diffs, while some w/ the LSD had the fins, and some didn't.
Take the car for a test drive and do a burn out....or hook a corner and nail the throttle.....
One Stripe - NO LSD
Two Stripes - LSD
That would be my preference. Unfortunately, the car I'm looking at is out of state (as in I am in NH and it is in CO). I plan on getting a pre-purchase inspection done, and was hoping I could have them take a quick picture while it's on the lift.
Ask for VIN.. run it at dealer. They will tell you.
But I like Callmiro's approach.
I have the Datacard, and it appears it does NOT have the LSD, but I was getting some conflicting info on what exactly was included w/ the P30 "package" (which I realize isn't really a package anymore but is still used "internally" by MB to denote the alcantara wheel, carbon spoiler, etc.)
Mine does not have LSD but it easily lays down two beautiful stripes. Don't use that as a indicator of having or not.
This.
OP -- Two options. 1 - Go to a dealer with the VIN and ask for the build sheet. 2- if the build sheet doesn't have option 471, LSD, then the only way it has one is if the seller installed one which I'd hope they'd know about.
You won't be able to tell just crawling under the car.
The whole burnout theory is bogus. It can work, but if you really want to know if there is an LSD then it is the last option short of cracking open the diff to see for yourself.
Don't overcomplicate this...there is most definitely a way to tell if the car has a limited slip without the datacard and without pulling the rear differential cover to look inside....you said "while they have it on the lift".... THIS is your key, a 2 post lift will give you all the info you need(actually so will a jack)....while it is in the air(or just the rear if they use a jack) with the key on but engine not running place the trans in neutral and with your hand spin one of the rear tires(doesn't matter which)....if the other tire spins in the opposite direction then the diff is open, if the other tire spins in the SAME direction you have a limited slip rear differential.... Simple as that
There is NO way to visually tell if you have an LSD. Even if the data card does not show that it came from the factory as an option, you still could have an LSD (OE or aftermarket). The only way to know for sure is to open the diff and have it visually inspected. Of an unknown car, this would be the ONLY way to absolutely sure. Although you could look at the bolts on the diff and see if they have been messed with. B/c they would have had to come off at least once to do the diff fluid change @ 2000 miles, or to install one. It would be a pretty good indicator, but the only way to know is to take a look at whats in the diff.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by jptaylor
Don't overcomplicate this...there is most definitely a way to tell if the car has a limited slip without the datacard and without pulling the rear differential cover to look inside....you said "while they have it on the lift".... THIS is your key, a 2 post lift will give you all the info you need(actually so will a jack)....while it is in the air(or just the rear if they use a jack) with the key on but engine not running place the trans in neutral and with your hand spin one of the rear tires(doesn't matter which)....if the other tire spins in the opposite direction then the diff is open, if the other tire spins in the SAME direction you have a limited slip rear differential.... Simple as that
There is NO way to visually tell if you have an LSD. Even if the data card does not show that it came from the factory as an option, you still could have an LSD (OE or aftermarket). The only way to know for sure is to open the diff and have it visually inspected. Of an unknown car, this would be the ONLY way to absolutely sure. Although you could look at the bolts on the diff and see if they have been messed with. B/c they would have had to come off at least once to do the diff fluid change @ 2000 miles, or to install one. It would be a pretty good indicator, but the only way to know is to take a look at whats in the diff.
And thats the truth, Ruth!
Um, no....and poor deceived Ruth
....and like Mort said it is a clutch/plate style limited slip.
....if I'm not mistaken you can even tell whether a limited slip is clutch/plate or a Torsen by using the same method I described above....the difference being that with a clutch/plate unit the tires will each spin freely at the SAME speed in the SAME direction,indefinitely...but if the diff is a Torsen unit the rear wheels will BEGIN to spin at the same speed in the same direction but if you begin increasing the spinning wheel's speed with your hand it will begin to slow down the OTHER tire as the Torsen vectoring system inside applies internal friction to the slipping wheel in an effort to equalize traction across both tires.
....and like Mort said it is a clutch/plate style limited slip.
....if I'm not mistaken you can even tell whether a limited slip is clutch/plate or a Torsen by using the same method I described above....the difference being that with a clutch/plate unit the tires will each spin freely at the SAME speed in the SAME direction,indefinitely...but if the diff is a Torsen unit the rear wheels will BEGIN to spin at the same speed in the same direction but if you begin increasing the spinning wheel's speed with your hand it will begin to slow down the OTHER tire as the Torsen vectoring system inside applies internal friction to the slipping wheel in an effort to equalize traction across both tires.
You need to slow down. I completely agree with the method that you described above. But how can you possibly say no to opening the pumpkin and looking?? Are you that dense?? Yes, there is no reason for OP to over complicate this whole issue. But to say that looking at the LSD itself is not a way to determine what you have is ludicrous!! Your quick denial and inaccuracy baffled me. So, just to get this right, you are stating that opening the diff and looking at the part is not a way of verifying wether you have an open diff or not?
Im not doing it, so it doesn't bother me. OP has ZERO knowledge of his car. I was offering up a way that he could be absolutely certain. And in the process, he could either add an LSD at that point while its open or at the very least know that the fluid has been changed if the car has one. Doesn't seem ****ing retarded. Seems like those are 2 pretty decent outcomes for opening the pumpkin. Especially if the OP wants an LSD.
There is NO way to visually tell if you have an LSD. Even if the data card does not show that it came from the factory as an option, you still could have an LSD (OE or aftermarket). The only way to know for sure is to open the diff and have it visually inspected. Of an unknown car, this would be the ONLY way to absolutely sure. Although you could look at the bolts on the diff and see if they have been messed with. B/c they would have had to come off at least once to do the diff fluid change @ 2000 miles, or to install one. It would be a pretty good indicator, but the only way to know is to take a look at whats in the diff.
And thats the truth, Ruth!
You didn't state that ^^this^^ was A way, you stated it was the ONLY way to visually verify that a vehicle has a limited slip, which is just not true....as I stated, and to which you agreed, you can most certainly verify visually if there is an LSD installed, without removing the cover. And as for your rant...calm down and let things sink in a little before popping off, I mean your last post makes out like you did not previously state that popping the cover was the "ONLY" way to know.... Your post was inaccurate and posed the potential for someone who was asking for real world advice in relation to making a large scale decision to overlook good cars for purchase strictly because they thought they would be required to open the rear diff housing on vehicles that aren't even theirs to make a details inspection when the same info can be obtained simply, quickly and without physically opening an intricate mechanical component of the car....it's ok, no one is mad at you, it happens to all of us...just don't lash back out with nonsense when you feel butthurt and corrected.
Don't overcomplicate this...there is most definitely a way to tell if the car has a limited slip without the datacard and without pulling the rear differential cover to look inside....you said "while they have it on the lift".... THIS is your key, a 2 post lift will give you all the info you need(actually so will a jack)....while it is in the air(or just the rear if they use a jack) with the key on but engine not running place the trans in neutral and with your hand spin one of the rear tires(doesn't matter which)....if the other tire spins in the opposite direction then the diff is open, if the other tire spins in the SAME direction you have a limited slip rear differential.... Simple as that
Well said! A variation of this goes like that: Jack the rear up, leave the tranny in P. Try to spin a rear wheel. If you can spin one, the other will spin the equivalent amount backwards. If you have a LSD, you cannot spin a wheel. It will be blocked.
Well said! A variation of this goes like that: Jack the rear up, leave the tranny in P. Try to spin a rear wheel. If you can spin one, the other will spin the equivalent amount backwards. If you have a LSD, you cannot spin a wheel. It will be blocked.
My understanding is if you pull one of the drive shafts and look in the hole like this LSD has this cross inside and open diff will only have one bar. Mine came from a car that had the LSD option but I am still not 100% sure either only way is to install it, my car is a 2008 so the likely hood of it having the LSD by accident is like impossible I tried all the jacking up tricks but I know when I am on ice only one wheel spins.
Here is an oem LSD, I am going to swap mine out this spring once the snow is gone. Took me a while to find it.
As far as I know you cannot tell from the outside whether the insert is locking or open.
BTW, you have the standard US housing, without any cooling fins. If you think you might drive the car hard, for example take it to a few track days, consider swapping the rear lid and add the so called rectifier (cooling fin attachment). That way the diff will be thermally much healthier. See the FAQ section for a detailed build thread with pictures and part numbers. Given you have the diff lying around waiting to be installed this would be the ideal time to do that. About 300 $ is all it takes.
03-24-2016, 01:34 PM
I was thinking about the cooler too but that's a bit overkill for my usage.
