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The automatic 8 speed has the open differential, the 8 speed auto transmission started in 2015, the manual transmission has the LSD differential.

I have a 2015 R/T Classic Plus 5.7L A8, it came with a 3.07 Open Differential, I swapped it out myself to a Mopar 3.09 Limited Slip Differential, using wheel ramps and jack stands. Note: Unless you have a high mechanical ability and a lot of common sense, I don't suggest doing it yourself, but it can be done.
What all parts besides the pumpkin did you have to change out? Axles, hubs, etc.? Any special tools needed?
 

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What all parts besides the pumpkin did you have to change out? Axles, hubs, etc.? Any special tools needed?
The 2015 up, already has the axles needed, you need to replace the bolts but you can forget replacing the bolts through the rear of the cradle because you cannot get the old ones out without dropping the entire cradle. You replace the long bottom bolts that hold the differential in place, and the bolts that secure the driveshaft to the differential hub. And when you order those from Mopar parts it is kinda confusing what they call a set is only 2 bolts with the locking ring, so you need to order 4 of those sets, the 2015 has an 8 bolt flange.

The LSD differential is about 25lbs heavier than the one you remove, so you have to come up with a way to lower it safely, I used 3/4" plywood and made a floor jack adapter with 1/2" x 10" carriage bolts to lower and raise the differential keeping it level.

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I bought a floor jack from harbor freight and bored a hole through the lift head to bolt the adapter to.

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This is the open differential coming out from under the car, if you look to the left you'll see that black handle bar which is excellent to release the right and left dust plates on the axles from the from the differential body. Bought that also from Harbor Freight along with the jack pictured, the only other thing you will need is a torque wrench.

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The bolt you see in this picture are the long bolts you replace there's another on the other side.

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The 8 driveshaft bolts, and you can see the other long bolt in this picture.

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This is an important picture if you intend doing this yourself, if you look at how the car is supported you'll see a jack stand just past the differential breather tube, (Which you transfer the breather tube to the new differential by the way), the car is finicky when you jack it up it is imperative you make sure you still have pressure on both jack stands as you do this. I wanted to be sure even if something went wrong the car would not fall on me because when you lower the old and raise the new differential in place the wheel have to be able to turn to properly align the splines into the differential, because the axles have CV joints on each end. That's why you see screw jacks, (what you see in the picture is duplicated on the other side), on the concrete blocks, and also you see a concrete block under the wheel with multi layers of plywood, you jack just enough on each side to remove one layer of plywood so the wheel can rotate, that way if it did fall, it will only drop the plywood layer you removed. Once both wheels turn freely, double check that pressure is still on the jack stands before you get under the car, and once you drop the differential free, replace the plywood you removed on each side and lower the car back onto the plywood.

I used nylon wire ties to hold the driveshaft over out of the way, do not just let it hang down. The orange straps you see are holding the axles up, don't allow those to hang down either. The carriage bolts will need to be height adjusted from the open differential to the LSD to account for the fins on the bottom of the LSD. If you make a plywood adapter plate like I did you can use the open differential under the car as a guide for where to bore your holes, but do not just bore 1/2" holes for the bolts bore 1" holes because the LSD is different and you'll need to reposition the alignment of the bolts to contact solid surface support of the differential. Keep in mind the new LSD differential is a solid 25lbs heavier that the open differential be careful. The videos I watched recommended 2 people when you put the splines back into the differential, you can do it by yourself just be sure the splines do not touch the rubber gasket seal as you go into the differential. You can feel when the splines fit into the the mating housing and you know it will go straight in from that point and you'll supply a little extra effort just before the spline is all the way in as the locking clip engages. That's all I can think of right now, I hope this helps you! Ry
 

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Dang I was just going to hold the new one in place while my buddy runs the 2 front bolts on.
Well if you are as strong as a Gorilla you may be able to do it like that, but the open differential weighs about 70lbs and the LSD about 95lbs. Once the axles are back inside the differential it's probably about 150+ lbs then. The biggest problem getting it back in place is not the easy front bolts it is getting it perfectly aligned, to thread back in the rear cradle bolts, once the rear cradle bolts are threaded all the way back in, then the front bolts will be properly aligned. You will fully understand once you actually get to that point of the installation, but the rear cradle bolts have got to be threaded back in first. That's why you need something that you can adjust to lift that bad boy up for you and hold it static in place, while you do what you have to do.

Edit: Also you need to estimate how much pressure it takes you to break loose the rear cradle bolts, you'll have to match that amount of wrench pressure as close as you can, because you will not be able to get a torque wrench back there.
 

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You will need some type of lift setup to hold the differential in place to thread in the rear cradle bolts, it is a tedious process you have to be extremely careful doing as the differential has to be perfectly aligned to even do it, and you do not want to cross thread those bolts, or you'll be up the creek without a paddle. As long as the threaded holes are in perfect alignment the bolts will go in fairly easy with finger guidance, that way you can feel any undue resistance to be sure you are not cross threading the bolts. If you leave about a 1/2" gap between the differential and the cradle you can easily see the bolts going into the threads, work one at a time getting both threaded in so you can see what's happening. Do not, tighten one and then try to get the other threaded, make sure they are both threaded in the holes. Once they are properly threaded you can alternate tightening each one a little at a time until you get them snugged up, but don't hard tighten at that point. Get the front bolts in as they have a little play, snug the front bolts up but don't tighten all the way, tighten the rear cradle bolts all the way, then tighten and torque the 2 front bolts.
 

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Torque Information:
Differential Drain and Fill Plugs = 26ftlb
Forward Mount Isolator Bolts = 48ftlb
Differential to Crossmember Bolts = 111ftlbs (You cannot get a torque wrench on those bolts without dropping the cradle, those are the bolts I suggested estimating the break loose pressure on).
There is a way to torque those bolts without removing the cradle by simply boring 2 access holes through the spare tire support bay, and sealing it back up when done, but I was not going to do that.
Propeller Flange Bolts as Mopar calls the driveshaft to differential hub bolts. = 49ftlbs (Tighten in a star pattern)

The LSD differential oil I used was Royal Purple Max Gear 75w-90, because it already had the Friction Modifier Additive in the oil, what you use is your choice, and it takes over 1 bottle to fill so you'll need 2 of whatever you go with.
 

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New LSD break in information:

For the first 100 miles let 60mph be your top speed.

The initial first 3 times you drive keep the distance between 15 to 20 miles, bring it back home, park it, and allow it to completely cool down, it gets hotter than your open differential did, that's why it has cooling fins forged in the bottom, this is setting the oil seals.

Ist time you take it out find an open parking lot, idle through 20 turns to the left, then idle through 20 turns to the right, then do 20 figure 8s idling through them. Trust me, you'll feel like an idiot doing it, but I followed these guidelines to wear in the gears, and I have zero whine from the rear end.

After the first 100 miles slowly increase your aggressiveness, speed and driving distance, it was suggested to change the break in oil at 500miles, but I ran mine 1,000 miles and it looked good when I drained it only microfine particles were in the dropped oil.

At 500 miles I did my first 0 ~ 60 and really hammered it, with traction control completely turned off, she left 2 beautiful tracks of rubber! :)

How you break yours in is up to you, some say break it in how you drive it, but what this monetarily cost me, not just in money but time, I wanted it to last as long as possible, and since I have no rear end whine, I'm happy! :)
 

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I would advise against LSD. I did some when I was a teenager and drove. Very dangerous. The center line was waving but the road was straight.
 

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I would advise against LSD. I did some when I was a teenager and drove. Very dangerous. The center line was waving but the road was straight.
IME, Mushrooms were similarly disorienting when operating motor vehicles. Although, IIRC, the center stripes would all stand up straight like traffic cones, but at least you knew when they were finally kicking in with that particular effect.
 

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LSD as tagged by Mopar is a Limited Slip Differential, it has nothing to do with drugs of any type.
 

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:rolleyes:

A Guy
 

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I do find this strange. A car with this much performance potential and they delete the LSD in the A8, theoretically the faster of the transmission choices???

Agreed that a car with Super Track Pack should also have it. An open diff can fry the inside tire coming out of turns. Again, maybe the computer traction control factors in somehow?
The idea of the auto as potentially FASTER in than a manual probably has nothing to do with this. In truth that smother auto transmission with extra gears and the ability to computer control how hard each shift "hits" the drive-train likely is a big part of why the LSD in a 5.7 auto was deemed unnecessary and removed as an option.

Rear gears face a tough life and stress due to 3 factors.

1. Torque and the multiplication delivered from the engine/ transmission combination

2. Stall speed of the converter in auto and of course the potential of the bang shifting and clutch dump speed in a manual.

3. Weight of the vehicle and tire size and grip.

I'd be shocked to learn that Dodge doesn't use these various rear gear set ups, both LSD and open in other vehicles beyond just it's Challenger and Charger too. So limiting choice as much as possible probably saves money when building cars and suvs across the line up.

Getting specific...the V6 and 5.7 deliver less torque than the bigger engines in the Challenger and they come factory delivered with the narrower tire and rims.

So while it's only a guess.......I'm betting the choice to eliminate the LSD in the 5.7 auto was little more than a cost saving measure in production and it was deemed unnecessary in the Automatic 5.7. You still get in in a manual because Dodge doesn't want or need the extra warranty claims on the broken rear gears coming in due to guys out there that you just know do 2,000 RPM and up clutch dumps off the line and then power shift their way through the gears.
 

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My 2016 RT Shaker has the Anti Spin Diff standard. Are you guys talking 2018 up here ? It’s listed on the window sticker as standard equipment.
 

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My 2016 RT Shaker has the Anti Spin Diff standard. Are you guys talking 2018 up here ? It’s listed on the window sticker as standard equipment.
If you have a standard, all of them get LSDs. Auto R/Ts are open diffs.

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My 2016 RT Shaker has the Anti Spin Diff standard. Are you guys talking 2018 up here ? It’s listed on the window sticker as standard equipment.
If you have a standard, all of them get LSDs. Auto R/Ts are open diffs.

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its’s an 8SP auto with STP and paddle shifters. Leaves a pair of streaks every time
 

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its’s an 8SP auto with STP and paddle shifters. Leaves a pair of streaks every time
Weird. I guess Dodge made it an option in 11 or 12 from what I just read. I was always under the assumption you couldn't get it with an automatic.

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My 2016 RT Shaker has the Anti Spin Diff standard. Are you guys talking 2018 up here ? It’s listed on the window sticker as standard equipment.
This has been a point of confusion for years. What you say is true, the LSD is indeed standard equipment on the R/T. And so is the 6-speed manual transmission and that's the problem. The minute you check the box for the optional automatic transmission then you no longer have a standard equipment car and the standard LSD is deleted and an open rear is put in it's place. You have an open rear, not LSD but the traction control can do a good enough job where it seems like you might.


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