Where to Start
What to Look for When
Purchasing Used AOD-E/4R70W and AOD Units
If you are searching the for a used AOD-E/4R70W or AOD transmission
to swap into your project vehicle (or for a performance buildup), this
section should prove helpful.
In addition to the specific tips below, please be aware that all AOD
and AOD-E/4R70W transmissions can have either a seven or eight tooth speedometer
drive gear machined into the output shaft. Generally speaking, vehicles
with 2.73-1 axle ratios may have an eight tooth output shaft. If unsure,
it would be wise to remove the extension housing and count the helical
teeth. Depending upon tire size used, an eight tooth output shaft may make
speedometer correction difficult for axle ratios lower (numerically higher)
than 3.27-1. Unfortunately, output shafts cannot be changed without disassembling
When looking for an AOD-E/4R70W transmission, the following tips apply.
If you are seeking an old-style AOD, the following tips apply. Also, remember
that most of these transmissions are quite old and crusty now, so choose
The bell housing pattern is different for a 4.6L or 5.0L/3.8L/4.2L engine
and the two are incompatible. The two case types can be distinguished by
looking at the starter flange area. If the starter has three attaching
bolts, the case fits only 4.6L engines. A two-bolt starter indicates a
5.0L/3.8L/4.2L compatible case (casting number may begin with "F4ZP", not
available before 1994).
Does the unit have a wide or standard ratio gear-set? This requires you
to know the original application or remove the pan and inspect the ring
gear through a drain-back slot. AOD-E transmissions built through 1995
share the same standard gear ratios as the AOD, except for the 1994-95
Thunderbird, 1994-95 F and E series trucks, 1995 Full Size Cars and the
1993-95 Lincoln Mark VIII. 1996 and later units are all wide ratio transmissions.
Valve bodies for 1992 cars have a different shift pattern ("P-R-N-OD-D-1",
like an AOD) than other AOD-E/4R70W units ("P-R-N-OD-2-1"), because these
cars had no Overdrive Cancel Switch.
3.8L V-6 AOD-E/4R70W transmissions have only one less clutch plate than
V-8 units and with our valve body kit are at least as strong as any AOD.
If you are planning to replace the clutches in your transmission, two new
pressure plates (less than $20) from the Ford parts department will make
it equal to a V-8 AOD-E/4R70W. Unlike the AOD, you neednít avoid buying
V-6 versions of the AOD-E/4R70W transmission.
Some trucks (and possibly a few Lincolns) use a one-inch-longer output
shaft than the Mustang and other vehicles.
Many AOD-E/4R70W units (especially later and wide ratio units) use an extension
housing with a larger output bushing. This housing accepts a slip yoke
with a larger outside diameter. This is not a major problem, as the slip
yoke or extension housing can be changed and all output shafts share the
same 28-spline profile as an AOD or C-4 transmission. An AOD-style extension
housing can easily be bolted onto an AOD-E/4R70W. The large bushing housing
bears a casting number beginning with "F3LP" for the standard length and
"F3UP" for the long unit. The small standard length housings are marked
with either "F2TP" or "E0AP". The small bushing long version is marked
as "E0TP" or "E0LP" and is probably only used with the AOD transmission.
V1.1 © Copyright 1994, 1995, 1998 by Karl
Baumann. All rights reserved.
Please see the Performance Guide Index (pguide.htm)
for complete copyright information.
Try to avoid pre-1988 models without rear-lube enhancement. It is likely
that planet bushing damage may have already occurred, mandating expensive
new gear-train parts as well as an updated output shaft.
1992-93 E and F series trucks (those with AODís and not E4ODís) contain
the strongest production AOD transmissions. Included is the two-inch wide
overdrive band (part of the Motorsport Wide Ratio Kit, or available as
a separate conversion kit from Baumann Engineering for close-ratio applications,
and highly recommended for full-throttle use of overdrive) and the
now-famous "A" overdrive servo.
All Thunderbird SC supercharged V-6 transmissions contain the "A" servo
(its original application) and the strong H.O. V-8 style clutches but still
use the 1.5-inch overdrive band.
In situations other than those listed above, any 1988 or later V-8 AOD
transmission (steer clear of the base V-6 units) should prove adequate
for most AOD buildups. Be warned, however, that most Lincolns and some
trucks use a one-inch-longer output shaft than the Mustang and other vehicles.
Naturally, you will have to re-use your vehicleís manual lever and external
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Created as new page on:
10/23/98 This page was last updated