please please i need all help i can get, drive train mopar chrysler 8.25 27 spline 10 bolt gears

Is there is a diff between the 69 to 75 stuff versus the 76 to 2004 stuff?
Yes. The earlier years are 27 spline and the later are 29 spline. I believe the year change you listed is correct.
I am not an expert so others can chime in on other differences but you will need the early kit.
I bought the Motive kit and the inner bearings were wrong. Had to get the PN off of the bearings I was replacing
but Napa had them in stock. Use timkins!!!!! I agree with others. Call Dr Diff.

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