The 8 1/4 thread

halifaxhops said
Got this fro Dr. Diff

As far as I know, there is only 1 pinion offset machined into all 8.25" housings.

2. There were 2 carrier offsets, however. One for 2.45 and higher gears, and one for 2.76 and lower gears. In other words, you can install 3.55 gears in a housing that originally came with a 2.45 ratio, as long as you install the appropriate carrier.

3. In 1997, the axle spline count increased from 27 to 29.

4. In addition, 2 different carrier bearings are required, depending on the year of the housing. You can press the later style bearings on an early differential carrier and vise-versa, however.

This information is listed in the tech archives at moparts.com
8 1/4"
Differential Early: LM102949/LM102910 (Til mid-75 with "S" on top of case)
Differential Late: A-36 (Mid-75-up, with large "L" on top of case)
Pinion inner: M802048/M802011
Pinion outer: M86649/M86610
Seal: 8516N

so basically any 8.25 rear end with 27 spline axles that came with a carrier with at least a 2.45 or higher gear ratio will accept 2.45 and higher gear ratio or a whole different 27 spline carrier with 2.45 or higher gear ratio.

but depending on the year of the carrier(like me with a early to mid 90s carrier ) you might have to switch the bearings on the carrier and if it has a tone ring you might need grind the teeth off or remove the ring.