In 1991 Ford introduced an electronically controlled version of the AOD known as the AODE and eventually referred to as the 4R70W. The introduction of the AODE/4R70W would usher in some significant design improvements and dependability over the previous AOD transmission. Although the AODE/4R70W transmission’s improvements have garnered a just worthy amount of respect, the electronics needed for conversions creates some challenges as well.
In 1993 the AODE would undergo a name change to 4R70W. Ford and other automakers decided to code the transmissions so that the name of the transmission actually gave information as to its characteristics; therefore, 4R70Wstands for 4 gears, Rearwheeldrive, 70 arbitrary number given by Ford for strength and Wide gear ratio.
The success of the AOD/AODE/4R70W can largely be based on the evolution of the transmission over time rather than an immediate success. This was especially true with a couple of advances that came about in 1993. The 4R70W featured an increased 2” inch overdrive band, thereby increasing strength and diminishing an obvious weak link. Another improved feature for the AODE was the "lockup" or torque converter bypass system. A “clutch type” system for the converter providing lockup was now instructed by the EEC controller. This resulted in less stress to the input shaft since the converter “clutch” offered a partial application or "slip". The introduction of improved gear ratios or Wide gear ratios was also introduced in 1993 vehicles. The gear ratios are: 1st: 2.84 :1 2nd: 1.55 :1 3rd: 1.00 :1 4th: 0.70 :1 Rev: 2.23 :1. These were a great improvement to the previous ratios of 1st: 2.40 :1 2nd: 1.47 :1 3rd: 1.00 :1 4th: 0.67 :1 Rev: 2.23 :1
There have been other improvements added to the 4R70W since 1993; the most prevalent was the introduction of the "Mechanical Diode" beginning with the 1998 models. Newer transmissions are commonly called 4R70E, 4R75W or 4R75E to differentiate them from previous “non E” models. The 4R75E/W therefore has greater torque capacity and strength than earlier models like the 4R70W.
As mentioned, the 4R70W has emerged as what can be a prime candidate for conversions; however, behind the silver lining there are some potential hurdles. First and foremost engine selection can be key. Obviously, the 4R70W is computer controlled. This may be inconsequential when using the accompanying engine that was mated to it, as the factory computer will already be in use. But what about the guy who wants to run an older engine like a carberated 289 or 302? In the past, this has been a deal breaker as the transmission is totally computer reliant. Solutions can found in the use of a “stand alone computer”. Both Baumann Engineering and Compushift offer small computers that control the transmission independently.
Advance Adapters offers several transfer case adapters for adapting the AODE/4R70W. Our AOD 88+ kits can be used with the AODE/4R70W but they also require a minor plug shift kit under part #716057. Since a majority of our kits include a new main shaft, typically it does matter if the 4R70W is 2WD Or 4WD. It is however important that the front bolt pattern matches the engine block of your choice.