To upgrade a '74 8.25 differential with 2.45 gears - to 3.21, it is my understanding I need to replace the carrier (inner guts) to one that accepts 2.71 and higher (numerically).
Jeeps 1996 and older with an 8.25 also have a 27-spline, which matches with my '74.

What else do I need to know to make this work? Could it be as easy as buying a set of carrier bearings, a 1996 and older carrier, and an R&P set?

For clarification, I want to change the ring-&-pinion - not the differential assembly.

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'68 Barracuda - taking advice on increasing street torque, power, & road handling. Click To See It

yup, should work fine. as long as spline count matches up. carrier didn't matter, what body the rear end was in. whether it came from a Duster, or a pickup or van or Cordoba, whatever.... as long as it was an 8-1/4 with the same spline count that you need and above the "break point," on ratio. and be sure you use a MATCHED SET of ring and pinion. Don't use the ring gear from the donor with your original pinion.

I believe there are 2 differential ring carriers for the 8.25" Chrysler axle.

I remember helping a buddy set one up with a 4.10 gear or something and we could not set the lash closer than like 1/8" or something ridiculous. We believe he had the 2.66-2.21 Carrier in there, and we did not know that at first.


So yes as Don said as long as you have the correct axle spline and 2.71 diff carrier it will work.

Greg

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http://www.youtube.com/hyperpack

Terrific, thanks gents!

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'68 Barracuda - taking advice on increasing street torque, power, & road handling. Click To See It