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Ford AOD transmission
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Ford AOD transmission
The AOD (automatic overdrive) is a four-speed automatic transmission, with the 4th gear as overdrive. Introduced in 1980, it was Ford's first four-speed automatic overdrive transmission. The gearset design is based on the Ford "X" automatic transmissions used during the 1950s, '60s, and '70s. The AOD replaced many of Ford's older transmissions, such as the C4, C5, and light duty applications of the FMX.
In 1962 Ford began working on a new type of automatic transmission that would emphasize fuel economy and driveability. The new transmission was built around the Ravigneaux planetary gearset of the "X" transmissions. Where many transmissions had a fourth gear added on as an afterthought, Ford's new transmission was designed with a fourth gear integrated into the gearset. Because it was based on the "X" transmissions, its gear ratios from 1-3 were the same, with the fourth being 0.67:1.
The transmission featured a split-torque application for third gear as well as a lockup in the torque converter. As Ford explained, "Engine power divides. Forty per cent is transmitted hydrodynamically, as in a conventional automatic transmission. The other sixty per cent is transferred mechanically by direct connection between the engine and transmission, which reduces converter slippage and thereby improves fuel economy....However, the torque converter is still in the power path to aid both smooth operations and torque multiplication for acceleration.
The XT-LOD transmission had been initially abandoned in 1966, but the design began again in 1974 because of rising gas prices. The project was shelved with a design that lacked a damper in the torque converter but, after the project was revisited, a damper eventually made its way into the final design. The transmission was introduced when Ford started to downsize its full-size line in 1979. Initially called XT-LOD (Extension Lock-Up Overdrive), its name was changed when revisited in 1974 to FIOD (Ford Integrated Overdrive) and then to its final name in 1979, the Ford AOD transmission.
Applications:
The AOD was redesigned with electronic controls in 1992, becoming the AOD-E. It was primarily intended for the new Modular V8 at first, but it was also adapted to the old AOD bellhousing for vehicles still powered by pushrod engines. While the AOD and AOD-E are like each other (oil pans, casings, bellhousing, and internals), they are not interchangeable with each other, because the AOD-E's shift points are controlled electronically from a combination of solenoids and the Powertrain Control Module (PCM), while the AOD's shift points are hydraulically controlled by a throttle valve rod.
Applications:
A revised version of the AOD-E Transmission was released in 1993 with the Lincoln Mark VIII. Unlike the AOD-E, Reverse, 1st, and 2nd gear ratios in the 4R70-W are numerically higher, giving the transmission a better mechanical advantage and, in turn, better take-off acceleration, better passing acceleration, slightly lower fuel consumption, and designed for better gearset strength; the 4th gear ratio in the 4R70-W is up 0.70:1 from 0.67:1. As a result, fuel economy is slightly increased and downshifting is slightly decreased for less wear. On vehicles powered by the 5.4L V8 engine, a stronger gearset is used than in normal duty 4R70Ws, and Torque Converter stall speeds are also slightly lower due to the 5.4L-engine’s increased low-end torque, as opposed to the 4.6L V8. In 1998, the intermediate one-way roller clutch was replaced with a mechanical diode due to durability concerns, thus providing extra holding capacity and longer service.
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Ford AOD transmission AI simulator
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Ford AOD transmission
The AOD (automatic overdrive) is a four-speed automatic transmission, with the 4th gear as overdrive. Introduced in 1980, it was Ford's first four-speed automatic overdrive transmission. The gearset design is based on the Ford "X" automatic transmissions used during the 1950s, '60s, and '70s. The AOD replaced many of Ford's older transmissions, such as the C4, C5, and light duty applications of the FMX.
In 1962 Ford began working on a new type of automatic transmission that would emphasize fuel economy and driveability. The new transmission was built around the Ravigneaux planetary gearset of the "X" transmissions. Where many transmissions had a fourth gear added on as an afterthought, Ford's new transmission was designed with a fourth gear integrated into the gearset. Because it was based on the "X" transmissions, its gear ratios from 1-3 were the same, with the fourth being 0.67:1.
The transmission featured a split-torque application for third gear as well as a lockup in the torque converter. As Ford explained, "Engine power divides. Forty per cent is transmitted hydrodynamically, as in a conventional automatic transmission. The other sixty per cent is transferred mechanically by direct connection between the engine and transmission, which reduces converter slippage and thereby improves fuel economy....However, the torque converter is still in the power path to aid both smooth operations and torque multiplication for acceleration.
The XT-LOD transmission had been initially abandoned in 1966, but the design began again in 1974 because of rising gas prices. The project was shelved with a design that lacked a damper in the torque converter but, after the project was revisited, a damper eventually made its way into the final design. The transmission was introduced when Ford started to downsize its full-size line in 1979. Initially called XT-LOD (Extension Lock-Up Overdrive), its name was changed when revisited in 1974 to FIOD (Ford Integrated Overdrive) and then to its final name in 1979, the Ford AOD transmission.
Applications:
The AOD was redesigned with electronic controls in 1992, becoming the AOD-E. It was primarily intended for the new Modular V8 at first, but it was also adapted to the old AOD bellhousing for vehicles still powered by pushrod engines. While the AOD and AOD-E are like each other (oil pans, casings, bellhousing, and internals), they are not interchangeable with each other, because the AOD-E's shift points are controlled electronically from a combination of solenoids and the Powertrain Control Module (PCM), while the AOD's shift points are hydraulically controlled by a throttle valve rod.
Applications:
A revised version of the AOD-E Transmission was released in 1993 with the Lincoln Mark VIII. Unlike the AOD-E, Reverse, 1st, and 2nd gear ratios in the 4R70-W are numerically higher, giving the transmission a better mechanical advantage and, in turn, better take-off acceleration, better passing acceleration, slightly lower fuel consumption, and designed for better gearset strength; the 4th gear ratio in the 4R70-W is up 0.70:1 from 0.67:1. As a result, fuel economy is slightly increased and downshifting is slightly decreased for less wear. On vehicles powered by the 5.4L V8 engine, a stronger gearset is used than in normal duty 4R70Ws, and Torque Converter stall speeds are also slightly lower due to the 5.4L-engine’s increased low-end torque, as opposed to the 4.6L V8. In 1998, the intermediate one-way roller clutch was replaced with a mechanical diode due to durability concerns, thus providing extra holding capacity and longer service.