Review & Install Video
Hey, guys. Stephanie with AmericanMuscle.com here with this Yukon Gear DuraGrip Posi rear diff for 28 spline 7.5 rears, or to break it down, '79 to'85 V8s and '86 to 2010 V6 Mustangs. This Posi unit from Yukon Gear is going to be a good option for the guys out there with a seven-five rear that are looking to replace their diff with an upgraded one that is a stronger, true Posi unit. This diff has composite discs and requires the use of 28 spline axles, which means that you don't have to upgrade over the factory units. This diff will get your car away from one wheel burnouts and give you a solid upgrade that's going to hold up better to more aggressive driving.
There are a couple of reasons to change or upgrade your differential. The first one is to move to a true Posi unit, so you have a consistent dual wheel spin instead of a single wheel spin. Another thing to consider is maybe you've got a stock diff and it's just getting old and chattering, or maybe you plan on hitting the drag strip and you've got some power that you'd like to cleanly get to the ground. But no matter what your reason is, this Yukon Gear diff is upgraded and it's slightly beefed up, and it's a quick solution to help you get power to the pavement through a true LSD setup. If we take a step back for a minute, the point of a limited slip differential, or LSD like this one here, is to allow both rear wheels to put power to the ground and get better traction to both rear wheels.
So the thought is, if there's any type of open diff transfer or uneven transfer of power and torque to one particular wheel over the other that'll create a useless wheel spin where the car loses it's forward momentum, the LSD is designed to eliminate that spin. It'll transfer the torque of both rear wheels evenly, which will have a few benefits in both street and track applications. This means a stable differential lock pattern that won't fail due to the upgraded components, no slipping, more durability, gentle transitions and even a quiet operation. I'm saying that this diff is a heavy duty diff because of features like the nodular case. The case is constructed from nodular iron, but more importantly, this diff also has forged 4320 steel internals and composite clutches. These are upgraded items that mean the diff will be dependable under aggressive driving, and in more of a heavy duty performance life. This also means a longer life span. The composite discs that I'm talking about here are the discs that are in the clutch pack, and the clutch pack is what activates the LSD. And more specifically, the clutch plates create the locking performance of the LSD that I spoke about earlier, so it's important that they will hold up to the spinning [SP] end.
Like I mentioned earlier, this diff is going to require the use of 28 spline axles, which is the spline count that the 7.5 rear comes from the factory with, so you aren't looking at having to upgrade your axles with this diff, which is nice. It's one less expense that you'll be facing when you're ready to move up to a diff like this. This is going to work for cars with a solid axle setup, and you'll need to reuse or grab a new seven-five rear gear set. This does not come with new aftermarket rear gears. One other note would be the recommended use of 75W90 rear gear oil, since this'll give you the same oil weight as factory, and you're going to need three quarts of that and four quarts of friction modifier for the initial fill.
When it comes to price, this rear diff is going to cost just over $400. It's actually one of the only two rear diffs for the seven-five rear that are currently available on this site, and it's a little more wallet-friendly of the two options. There is always the other option of upgrading to an eight-eight rear and 31 spline axles if you have the torque and power to justify that, but that's most likely going to be a little bit more expensive depending on which setup you choose to go with, and considering the other items that you'll need to make the switch complete. As far as the install, you're going to need some experience with this one. You need a few different wrenches and sockets, but an impact gun is going to help you speed things up here, even though you can do this install with all manual tools if you wish. A lift would also really help and you're going to need a torque wrench to do this properly. Another thing to consider here are proper tools like a dial indicator, bearing pullers and press, pinion nut socket, ring gear bolt socket and items along those lines just to avoid any part damage. You're looking at about four hours time and a three out of three wrenches on the difficulty meter.
Going over a general install, you're going to need to get to the diff itself, so this means pulling the rear wheels, dropping the rear brake assemblies, and draining and removing the rear diff and cover, so you'll need something to drain into. The axles will need to be pulled out of the diff, and the diff will need to be removed. The shims that are on each side of the diff bearings will need to be installed the exact same way, so keep track of those. You're looking at some diff assembly adjustments, such as pinion depth, pinion bearing preload, backlash and carrier bearing preload, and also some seal prep. Then you'll have a pinion trial assembly, an initial carrier assembly, followed by adjusting the backlash. And backlash is the amount of ring gear that can rotate forward and backwards when the pinion gear cannot move.
Now this is obviously a quick overview of the install, but I wanted to give you guys an idea of what it would take so you can make a decision as to if you wish to install this for yourself or take it to a shop. Wrapping things up here, Yukon Gear Posi rear diff is a seven-five rear diff that gives you an LSD setup with composite discs that's going to use with 28 spline axles. It's an upgrade over the factory diff, and this diff is a good option for those looking for a maintenance replacement or those looking for something to make sure that you can get some extra torque planted squarely to the ground. And you can check it out some more right here at AmericanMuscle.com.
Duragrip Posi Differential.
Stop doing those ridiculous and humiliating one wheel burn outs by upgrading to a Yukon 7.5in 28 Spline Duragrip Posi Differential from AmericanMuscle. A Limited Slip Differential (LSD) sometimes referred to as a "Posi" will allow both rear wheels to plant the power to the pavement giving you better traction and more impressive burnouts.
Featuring a case constructed from nodular iron, this Yukon Gear Duragrip Limited Slip Differential boast forged 4320 steel internals and composite clutches for dependable heavy duty performance and long life.
This 7.5" Yukon Gear Duragrip Posi Differential will fit solid axle equipped Mustangs, including 1979-1985 V8 and 1986-2010 V6 models. Requires use of 28 spline axles.
Application Note: 1979-1985 V8 and 1986-2010 V6 Mustangs came factory equipped with 28 spline axles.
You will need to reuse your factory 7.5” gear set, or upgrade to a set of our 7.5" rear gears
, required for this Limited Slip Differential. No aftermarket gears are included. For normal driving conditions we recommend you use 75W 90 rear gear oil. This will give you the same oil weight as factory. For colder temps or race use try 75w 140.
- What's in the Box
- (1) 7.5" Limited Slip Differential
- Installation Info
Installation Time: (approx) 4 Hours
Difficulty Level:Mechanical expertise or professional installation required.
- Tech Specs
- 7.5" Limited Slip Differential
- Heavy Duty
- 10 bolt cover
- Requires 28 spline axles
- Requires 3 quarts gear oil
- Requires 4 ounces of CM-19546-A1 friction modifier with initial fill
- Fits solid axle rear suspension
- Will it fit my Mustang?
- Other - 79, 80, 81, 82, 83, 84, 85, 86
- V6 - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10
Fits 1979-1985 V8 and 1986-2010 V6 models.