8 1/4 rearend posi unit

Syleng1 said

What ratio as there are two possible options.
I believe the 3:55 and lower is one offset and the 3:21 and higher is another.
If I am off please correct.

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The numerically-low Sure Grip unit only fits 2.2x and 2.4x-series gears and is a bit of an oddball, being introduced with the A99x transmissions with the 2.74:1 first gear. Mega-steep axle ratios and a deep first gear were Chrysler's financially-strapped end-around to developing an overdrive automatic transmission.

All other ratios, 2.76 & numerically higher, used the same differential through 1996. For '97, the axle spline count changed from 27 to 29, so those later Dakota/Ram Sure Grips won't accept muscle-era axles.