05/11/2026
Gear Vendors Overdrive vs AOD Transmission Swap, 1968 Mustang California Special
https://www.youtube.com/watch?v=yprxkwgA_VQ
Gear Vendors is doing an install on a 1968 mustang California Special, this car has an AOD in it, it came with a C4, we are going to put the AOD back in it with a converter and a Gear Vendors unit for better performance. The AOD is commonly used because people want overdrive, so they have someone build them an AOD, the AOD has wide ratios, the c4 is close ratios, the AOD has a really low first gear, but 2nd gear is far apart, it really drops heavy into the next gear. If the AOD swap was a tenth of the price of a Gear Vendor it would make perfect sense, but some people spend 1/2 or 3/4 as much as a Gear Vendor, sometimes just as much as a gear vendor install for an AOD Swap. A C4 was one of the best transmissions that Ford ever built for performance, the Gear Vendors add on overdrive unit can handle vehicles with 2,000 or even 2,500 hp, and is warrantied even with drag race use.
An AOD in it’s original application, in a fuel injected car, with properly adjusted linkages, is still less than an ideal transmission, because it has those three wide ratios and then an overdrive, but in a swap it is unlikely that the custom linkages are going to be made to make it work right because of cost and time. In different throttles it will behave very differently, under light throttle, it will 1, 2 quickly, spend a long time in 3, and then when you are off the gas it drops right into overdrive, with a little faster acceleration it briefly stays in one, it will stay in second for a long time and then dump into 3, then 4. With fast acceleration it shifts without revving up each gear.
People get an overdrive with the AOD, and are happy about that, but are missing out with its long shifts. The AOD is good for cruising down the highway, and that is about it, Gear Vendors gives you overdrive with the best performance transmission for your vehicle. In a 68 Mustang, there is no better transmission behind a small bock than a C4 transmission, the close ratios give it high performance advantage, and big engines make too much power for the AOD to live with.
On the freeway you will find out just how far apart the gears are in the AOD, instead of banging through some gears and staying in the power band, it is going to stay in one gear for a long time. The AOD was deigned to deal with the requirements of Corporate Average Fuel Economy, a very low starting gear, then a dump into taller ratios, which will get mileage on a fuel injected car, whereas the C4 and C6 were designed for performance - "how fast can we go in the quarter mile?", "what is best for passing?". Call (800) 999-9555, or search gearvendors.com.
Gear Vendors site:
https://gearvendors.com/index.html
:
https://www.sweetingperformance.com
Gear Vendors is doing an install on a 1968 mustang California Special, this car has an AOD in it, it came with a C4, we are going to put the AOD...