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This page is for informational purposes only. We no longer recommend or provide support for AOD builds/swaps other than specifically for our valve body kit.

Performance Guide

Section 3: AOD/AODE/4R70W Upgrades

For Improved Performance and Durability

The AOD-E/4R70W transmission has great performance potential and responds well to minor upgrades. In many cases, only a simple valve body calibration upgrade and transmission oil cooler installation are necessary to extract maximum performance and durability from this versatile transmission. The factory torque converters used with the AOD-E/4R70W transmission perform much better than their old AOD counterparts while the AOD-E/4R70W internals are also greatly improved. The result is that the AOD-E/4R70W has all of the advantages of a modern four speed electronic automatic transmission without the shortcomings that have always stigmatized the AOD.

More extensive modifications require transmission removal and may involve the installation of a heavy duty direct clutch pack, exotic friction materials, higher stall-speed torque converter, or a wide ratio gear-set (4R70W transmissions are already wide ratio equipped). To extract the maximum potential from your transmission, these upgrades can be performed as required. The following upgrades are applicable to both AOD-E/4R70W and AOD transmissions in most contexts. For AOD transmission applications, please read the section concerning AOD-specific upgrades. The AOD-specific upgrades, many of which involve the installation of AOD-E/4R70W components into an AOD, solve some of the problems that were corrected with the introduction of the AOD-E/4R70W transmission.

Shift Improvements

The non-synchronous 1-2 and 2-3 shifts of the AOD-E/4R70W and AOD give them a potential for shift quality unknown to most other Ford transmissions. However, the soft valve body calibration of these transmissions hides the performance potential within. Fortunately, a few simple valve body revisions can give the AOD and its descendants a new lease on life. In addition, these revisions can be done in varying degrees to suit the individual.

For all performance build-ups, we recommend our ReCal-Pro&trade AOD or AOD-E/4R70W valve body recalibration kit as a starting point for both performance and durability improvements. The firmer shift quality and enhanced line pressure control will greatly extend the life of your transmission's clutches and bands (especially the old AOD's ill-fated overdrive band). Additionally, the kit's ability to raise full-throttle shift points (AOD only) will often eliminate the need for manual shifting and its resultant inconsistency. Performance benefits can be realized from every feature in the ReCal-Pro™ AOD or AOD-E/4R70W valve body recalibration kit.

The AOD-E/4R70W valve body provides a reliable and consistent platform for calibration upgrades and the Baumann Engineering ReCal-Pro™ AOD-E/4R70W valve body recalibration kit provides a means to custom calibrate the AOD-E/4R70W to performance specifications while greatly increasing the transmission's life-span. Shift-point and other enhancements are handled by our US Shift™ Electronic Transmission Control System, which provides the ultimate performance transmission solution.

Direct Clutch Improvements

Because of its small diameter, the direct clutch is a weak link in these transmissions (especially the old AOD). This durability problem can be solved by increasing the quality and quantity of direct clutch plates while installing our ReCal-Pro&trade valve body recalibration kit with cutback elimination. The direct clutch Power-Pack kit from Alto allows up to seven friction plates to be fitted to the original AOD five-plate cast-iron, direct-clutch drum. Certain 1988-1991 vehicles use a six-plate cast-iron drum and 1992 and newer AOD's as well as all AOD-E and 4R70W transmissions use a stamped-steel (mandatory for wide-ratio applications) direct-drum, either of which will accommodate up to eight friction plates using the Alto kit. It is especially important to check clutch pack clearance when changing clutch pack components. Selective snap rings, available from Ford, can be used to "dial-in" the correct clearance. The Alto heavy-duty direct-clutch pack kit (p.n. A-1 for cast-iron direct-drums and p.n. A-2 for stamped-steel drums) should be combined with an OEM quality overhaul kit, such as our OH-1 or OH-1E.

When your transmission is disassembled, it is imperative that you carefully inspect your direct-clutch drum for input spline wear. If you notice any wear of the splines (resulting a sloppy fit with the direct input shaft or stub shaft) or if the splines are not flush with the front of the direct-clutch drum "snout" (see figure at right), you should replace the direct-drum assembly. This recession of the direct-drum input splines can be dangerous if left unchecked. In severe cases, the direct input shaft or stub shaft will be allowed to walk rearward until it contacts the front of the output shaft, blocking the lube feed orifice in the end of the output shaft. The resultant lube starvation will cause undue wear of the planetary bushings and will eventually lead to complete gear-train failure.

Ford no longer services cast-iron direct-clutch drums. As a result, all direct-drums are serviced by the stamped-steel drum conversion kit, Ford p.n. F2AZ-7F283-A (already included with the Ford Motorsport wide ratio gear-set).

Wide Ratio Gear-set

  Standard Ratio Wide Ratio
First Gear 2.40-1 2.84-1
Second Gear 1.47-1 1.55-1
Third Gear 1-1 1-1
Fourth Gear 0.67-1 0.7-1

For the more intense AOD or AOD-E upgrades, the 4R70W wide ratio gear-set may be installed. This gear-set is standard in the 4R70W (AOD-EW) transmission and is the item that distinguishes a 4R70W from an AOD-E unit. The ratios of the wide ratio gear-set compare to the standard AOD and AOD-E ratios as shown in the table at left.

To determine the "effective" first-gear-ratio improvement derived from using the wide ratio gear-set in a given application, simply multiply your rear axle ratio by 1.183 to obtain the equivalent standard gear-set axle ratio. In other words, a 3.27-1 axle ratio with a wide ratio gear-set will provide the equivalent of a 3.87-1 axle ratio with a standard ratio gear-set in first gear while providing identical ratios (and resultant cruise RPM’s) in third and only slightly different overdrive ratios. Essentially, the wide ratio kit makes your vehicle act as if it has a lower (higher numerically) axle ratio for maximum acceleration without sacrificing fuel mileage and increasing engine wear as a rear end gear swap would do. For most mild street vehicles, the wide ratio gear-set works best with a 3.27 or 3.55-1 rear axle ratio.

AOD-E transmissions built through 1995 share the same standard gear ratios as the AOD, with the exception of the 1994-95 Thunderbird, 1994-95 F and E series trucks, and the 1993-95 Lincoln Mark VIII which already have the wide-ratio 4R70W gear-set (thus the parts source for Ford Motorsport's wide-ratio kit). Starting with the 1996 model year, standard ratio AOD-E transmissions are no longer manufactured and only 4R70W wide ratio transmissions are produced.

Another valuable aspect of the Ford Motorsport Wide Ratio Upgrade Kit is the supplied four-friction intermediate (second gear) clutch pack and special "DYNAX" clutch frictions. By merely installing the included intermediate pressure plate (F3LY-7B066-A), any AOD or AOD-E can be upgraded to add one more friction plate than standard V-8 fare. The "DYNAX" intermediate clutches are standard equipment on all 1994 and later AOD-E/4R70W transmissions and are reportedly capable of providing better engagements with longer wear life. These parts can also be purchased separately from your Ford dealer to upgrade a standard ratio transmission.

AOD-E applications that have been converted to the wide ratio gear set can benefit from the installation of our US Shift™ electronic transmission controller or a custom powertrain control "chip". The US Shift™ TCS provides complete control over all shift points in any application and is completely "wide ratio aware". The US Shift™ TCS can also be calibrated to work with any transmission gear ratios or vehicle combination.

AOD full-throttle shift-point strategy with the Motorsport wide-ratio gear-set is different, but not impossible. For example, most factory AOD Mustangs shift into second gear at a full-throttle RPM of 4900 (+/- 200 RPM) and roughly 4500 RPM from second to third. A switch to the wide-ratio gear-set will increase the 1-2 shift point by 18.3% (multiply 4800 RPM by 1.183 to obtain a new shift point of about 5680 RPM). The 2-3 shift point will be similarly raised by a factor of 5.4% to produce a full-throttle 2-3 shift at about 4750 RPM.

If the 5680 RPM 1-2 shift-point is a little rich for your engine's blood, you may lower it by using a different governor (the E2AZ-7C063-B medium-speed or the E8AZ-7C063-A low-speed unit). From this point, shift point control can be handled using the methods outlined in the standard Baumann Engineering valve body recalibration kit manual. Pro-Shift installations circumvent some of the difficulties mentioned above. For more information on wide-ratio gear-set installations or availability, please contact Baumann Engineering.

Specific Upgrade Details for AOD Transmissions