The AOD (for automatic overdrive) is a four-speed automatic transmission with overdrive. Introduced in 1980, it was Ford’s first four-speed automatic overdrive transmission. The 4R70W stands for 4 gears, Rearwheeldrive, 70 stands for the 4th gear ratio, and Wide gear ratio. It has lower 1st and 2nd gear ratios for better take-off acceleration and improved gearset strength.
The AOD was used originally on ’80s and early-’90s Ford, Lincoln, and Mercury products and in the F-series pickups and E-series vans as well. Because the AOD is basically a retooled C-4, many classic car owners have discovered they can substitute this overdrive transmission into their ’60s and ’70s production vehicles relatively easily and reap the benefits of a lower final gear ratio and decreased wear and tear on their vintage small-block V-8 engine. Theres more parts to take off of this but I will do that when the rebuild kit gets here, just to make sure I get the right parts.