8-1/4" Limited Slip

BudW

Moderator
Staff member
Joined
Mar 4, 2012
Messages
5,121
Reaction score
1,485
Location
Oklahoma City
I was browsing for some parts for my ride, and ran across this:
POSI CARRIER DANA SPICER 27 SPLINE TRAC LOC DODGE CHRYSLER 8.25 INCH 10 BOLT | eBay .
Screenshot 2021-03-10 102557.png

Chrysler's 8¼” differential, from '68 to '96 use 27-spline axles.
'97 and up vehicles use 29-spline axles – which makes finding axles and limited slip carriers (for FMJ's) a bit hard to find, sometimes.
The 8¼” Ring and Pinion Gear sets are the same from '68 and up.

I did some digging and it appears Dana/Spicer has recently re-introduced the 27-spline limited slip carrier again. I might recommend anyone looking for a limited slip carrier for your 8¼” differential, to get one now, while they are still available – for I don't foresee this sticking around long (and hopefully I'm wrong on this).
On top of that, this unit is the rebuildable clutch design instead of the metal on metal cone design that Chrysler originally used for our cars (that came with limited slip).

Here is some details on the two units. Green is what will fit (8¼”) FMJ's and red will not (29-spline – DO NOT USE).
Screenshot 2021-03-10 102457.png

If you can't read the part number, it is d/s75101x
Screenshot 2021-03-10 102519.png


I think I might just grab one of these.
BudW

Edit:
I just noticed it says this is for “all gear (ratios)” - but it is not. The 2.2 nor 2.4 gear ratio will not work with this carrier.
If you have a 2.2 or 2.4 ratio, then this is the perfect time to upgrade to a 2.9 or lower gear set.
 
Last edited:

Camtron

Well-Known Member
Joined
Apr 25, 2019
Messages
1,814
Reaction score
1,376
Location
US
I ordered mine from, Drivetrain America for $330 with shipping & tax about a year ago but, they no longer list them in stock. Crazy what the last year has done to stock and supply chains.

B22B10AC-E15A-4C23-A5FA-16B6545085DC.jpeg
 

Gearhed

Well-Known Member
Joined
Jul 2, 2020
Messages
73
Reaction score
33
Location
Salem, NY
Here's something that's odd: 97+ xj cherokees, Dakotas, durango's, and even some light duty 1500s got the 29 spline chrysler 8.25.
However the liberty's, which came out a few years later, seem to be 27 spline, IIRC. They are also factory disc brake, but none are lsd as far as I know.
My 5th Ave is going to be getting a 29 spline xj unit at some point soon, currently piling up the parts needed to do the swap (got plates and perches, need to get b body shocks and build a driveshaft)
 

BudW

Moderator
Staff member
Joined
Mar 4, 2012
Messages
5,121
Reaction score
1,485
Location
Oklahoma City
Are you going to get custom axles made (for the 29-spline carrier)?
 

Gearhed

Well-Known Member
Joined
Jul 2, 2020
Messages
73
Reaction score
33
Location
Salem, NY
No, I've got a 7.25 in mine right now. being a Jeep guy, I got an entire xj 8.25 rear from a 2000. I'll be welding new perches on it and installing sometime this spring. From my measurements, it's roughly 1" wider overall compared to our cars, which shouldn't be an issue, it'll just bring the tire 1/2" further out on each side, which will help the looks IMO. The 29 spline rears are considered to be roughly the same strength as a ford 8.8, dana 44, and gm 8.5 10 bolt. They're pretty stout
 

Duke5A

Well-Known Member
Joined
Apr 6, 2018
Messages
1,638
Reaction score
855
Location
Michigan
No, I've got a 7.25 in mine right now. being a Jeep guy, I got an entire xj 8.25 rear from a 2000. I'll be welding new perches on it and installing sometime this spring. From my measurements, it's roughly 1" wider overall compared to our cars, which shouldn't be an issue, it'll just bring the tire 1/2" further out on each side, which will help the looks IMO. The 29 spline rears are considered to be roughly the same strength as a ford 8.8, dana 44, and gm 8.5 10 bolt. They're pretty stout

Is that a disc break axle? Don't forget the distribution block if it is. Inline Tube sells one for rear disc that is an exact replacement for the factory proportion valve. Bolts right into place. Another benefit of some of the parts under our hoods being GM pieces.
 

Gearhed

Well-Known Member
Joined
Jul 2, 2020
Messages
73
Reaction score
33
Location
Salem, NY
No, mines drum brake. Rear disc was uncommon on xjs, usually a limited or cherokee country only.
 

88_AHB

Well-Known Member
Joined
Sep 24, 2018
Messages
286
Reaction score
27
Location
West coast
Might be a little off topic but, I know a 29 spline would be considered a stronger axle than a 27 spline. Would you guys think this difference is worthwhile in durability and holding up to more HP? I know of course there's various factors that come into play with axle longevity such as driving conditions,gearing, power, weight etc. I've been contemplating upgrading my 8 1/4 to 29 spline inners (custom axles) or swap a 97-up axle out of a dakota etc. Just something that i've been thinking of before re gearing.
 

Gearhed

Well-Known Member
Joined
Jul 2, 2020
Messages
73
Reaction score
33
Location
Salem, NY
You wouldn't want to use a dakota one, it's wider and a very weird 6 lug pattern. Took some accurate measurements, and the xj cherokee unit is actually within 1/4 inch of overall width of our cars, much closer than I originally thought. I'd almost be willing to bet that the 97-earlier xj unit is the same exact housing as our cars have. As far as strength, in the 4x4 world the 29 spline unit is considered to be as strong as the dana 44, and almost as strong as an 8.8 ford. I don't have an FMJ 8.25 to verify, but I would guess, based off my measurements of the 7.25 in my 5th, that if you put a 29 spline carrier in the FMJ housing, then you could probably use stock length xj axles with just a wheel bearing change. If someone ever has an axle shaft out of their stock 8.25, and wants to take some measurements, I'll measure my 29 spline
 

Mikes5thAve

Well-Known Member
Joined
Mar 3, 2020
Messages
1,374
Reaction score
538
Location
Canada
If you already have 8 1/4 I wouldn't bother doing an upgrade just to get the 29 spline count unless you've had problems in the past. Stock 8 1/4 is pretty durable as is.
 

dm330

Well-Known Member
Joined
Sep 11, 2021
Messages
137
Reaction score
52
Location
Salem, OH
Just got an email from Randy's and checked other sites online, the Yukon Limited Slip YDGC8.25-27-1 is back in stock for anyone wanting a limited slip for their 8 1/4 27 splines.
 
Back
Top