ADVANCE ADAPTERS INC.
P/N: FORD AOD
P.O. Box 247, 4320 Aerotech Center Way
Paso Robles, CA 93447
Telephone: (800) 350-2223
Fax: (805) 238-4201
New Item: (8/94)
PAGE 1 OF 5
Page Rev. Date: 08-08-94
FORD AOD AUTOMATIC TRANSMISSION
INFORMATION
USING THE NEW STYLE SHAFT 1988-89:
If you elect to update your AOD output shaft to the newer design that has the additional hole, you must change the
valve and spring assembly. We have listed the three different valve and spring assembly part numbers that correspond
to the various governor assembly sizes. The information listed below is a direct reprint from the Ford notice
concerning AOD Governor Interchangeability.
A.O.D.
INTERCHANGEABILITY
When using this output shaft to service 1983-87 transmission models, rework the governor
assembly using the supplied valve and spring assembly kits.
Identify the governor being reworked and select the proper governor valve and spring kit from
the information below.
VALVE & SPRING DIAGRAM
ASSY. KITS
(See below)
E7SP-7G495-DA
E7SP-7G495-CA
E7SP-7G495-AA
A
A
B
SPRING COLOR CODE VALVE I.D.
YELLOW
NONE
NONE
.250 DIA.
.250 DIA.
.175 DIA. STEP.
For disassembly and assembly of governor, see Volume D, Section 17-20 of the appropriate Car Shop Manual or Volume A, Section 17-20 of the appropriate Truck Shop Manual.
To service 1982 and prior models, use new Governor Assy. (-7C063).
DIAGRAM A
DIAGRAM
B
STEP
SPECIAL NOTE:
The components packaged in this kit have been assembled and machined for specific type of conversions. Modifications to any of the components will
void any possible warranty or return privileges. If you do not fully understand modifications or changes that will be required to complete your conversion, we strongly recommend
that you contact our sales department for more information. This instruction sheet is only to be used for the assembly of Advance Adapter components. We recommend that a
service manual pertaining to your vehicle be obtained for specific torque values, wiring diagrams and other related equipment. These manuals are normally available at automotive
dealerships and parts stores.
This is something that no one likes to see...
fried friction. Our modifications will help prevent this injustice to AOD owners.
To most people, this may look like a bionic pizza, but it is actually a high-quality rebuild kit from
Trans Parts in Sarasota, Florida. This kit contains components from the same manufacturers
that supply them for Ford, at a much lower price. A rebuild kit such as this should be the
foundation for any transmission build-up, allowing you to start with a "fresh" transmission.
A 1/4-inch drill is being used to counter-bore
the governor oil feed passage, allowing the
installation of a filter screen supplied with the
rear lube kit. The filter is needed because oil
from the governor feed circuit is now used for
rear lubrication and must be free of debris.
Of course, removal of all debris created by
drilling is critical. And while your AOD is apart,
be sure to check this bore in the rear of the
case for wear. The governor and direct clutch
oil feed rings run in here, and the teflon oil ring
used in some transmissions may wear deep
grooves in the aluminum. If your case is worn,
you will either have to replace it or have a transmission shop install a repair sleeve. Fortunately, new cases from Ford re not as expensive as you might think. Be sure to use the cast
iron oil rings when reassembling your transmission.
A comparison of forward clutch drums shows the higher groove in the 351 "police" drum (at right)
shown by the rulers, which raises the retaining ring, allowing five clutch friction plates to be fitted
rather than the usual four.
Shown here is the stock governor compared
to the Mustang GT assembly. Looking closely,
you will notice the valve and spring on the GT
unit (top right) are slightly different than the
stock unit, allowing slightly higher shift points.
The GT governor is included in the Motorsport
rear lube kit.
Shown here is the Transco direct clutch pack
kit (right) compared to the standard replacement clutch plates. This kit allowed us to use
seven clutch friction plates in our five-plate
direct clutch cylinder. Note the absence of
cross-hatched grooves.
Installing the clutch pistons can be tricky business indeed, due to the inward facing lip seals
(similar to drum brake wheel cylinder cups).
The aid of special seal installer tools is a must,
but if you are lacking such resources and have
tons of patience, you can improvise. Use
stripes of thin plastic wrapped around the inside and outside seals to guide them into position. See-through plastic report covers are
excellent for this purpose.
SUPER FORD May 1990
23
Adapting the AOD to
non-stock applications
The AOD will generally bolt into most vehicles, but a few problems may arise. For starters, your stock block plate and flexplate will
probably work fine, just be sure that you use the
correct flexplate for your engine (small-block
Fords are balanced in a variety of ways). Though
the transmission crossmember must be moved
rearward to fit the rear mount of the AOD, the
stock transmission mount will usually work.
Moving the crossmember is as simple as changing to a rear set of holes in some vehicles, but
may be very involved for other applications, such
as unibody cars. The good news is that the drive
shaft will seldom need shortening. The short
extension housing AOD has the same overall
length as most regular Ford automatic and
manual transmissions and can even directly
replace some of the Japanese-built units used in
four-cylinder applications.
24
other serious problems.
Probably the most confusing aspect of
adapting an AOD is making the throttle valve
(TV) linkage operate correctly. Since the AOD
does not use a vacuum modulator to sense
engine load (thus determining shift points and
shift quality), it must have a direct link to the
throttle, allowing it to determine engine load from
throttle position, rather than manifold vacuum.
For vehicles without multi-port fuel injection, a
rod (similar to the kick-down rod used with most
other Ford automatics) is used.
A common
problem that arises when upgrading to a performance carburetor on a factory AOD-equipped
vehicle is that the TV rod must operate through
the entire through a small portion of its full range.
Do not let the similarity with the kick-down rod
fool you; it is impossible for the AOD to operate
without the TV rod tracking the entire throttle
range.
Failure to do so will cause either
excessive shift points, a failure to downshift out
of overdrive during deceleration (causing engine stall), transmission failure, or
There are a few methods that can be used
to adapt the AOD's TV linkage to a non-stock
engine. The first method is to connect the TV rod
to the carburetor kick-down linkage while modifying the carburetor linkage to permit travel of
the kick-down arm directly with the throttle (i.e.
bolt them together). It is critical that you ensure
the ratio is correct, resulting in the right amount
of travel of the TV lever at the transmission for
the entire throttle range. The best way to check
this is to compare your new carburetor side-byside with a stock AOD carb or throttle body. If the
distance from the center of the throttle shaft to
the TV rod connection point is equal, then the
carb will probably work. It is also important that
the TC leer on the car points in about the same
direction as the stock unit (for example, if at idle
the linkage on the stock carb is pointing to 11
o'clock, the new carb's linkage should also point
to 11 o'clock). If the arm on your carburetor will
not work, or if it does not have one, you can
probably fabricate and attach one, keeping the
above parameters in mind. Always be sure to
include some way to adjust your linkage.
If a TV rod proves to be difficult or impossible to adapt, you may be able to adapt a TV
cable from a multi-port EFI application. You will
want to look at several different vehicles in an
effort to find a cable length and configuration that
best suits your application. Then, order the
cable with the correct brackets and transmission
lever from your Ford dealer. If the ratio os
correct, you may be able to operate the TV cable
directly from the accelerator pedal. Other options include the use of brackets in front of the
throttle linkage or under the throttle linkage. The
cable allows freedom to make special brackets
and the like, for use in tight quarters. If you are
using a multi-port EFI engine (even if originally
equipped with a manual transmission), the stock
cable for the application will bolt right on.
In order to remove and install clutch pistons and
return springs, a tool is needed to compress the
spring, allowing the retainer to be released safely.
This compressor tool was easily fabricated from 7/
16-inch threaded rod, washers and a flat steel plate.
Be sure to change all clutch piston seals while your
transmission is apart, because they fail with age.
It is good practice to soak all of your new clutch
friction plates in fresh ATF prior to installation. A
half-full ATF bottle with a slot cut in the side (as
shown) makes a handy tool for soaking your clutch
plates. The fabricated compression tool mentioned
in the caption at left is shown in the upper right
corner of this photo.
SUPER FORD May 1990
A-OK AOD
because line pressure (the main fluid pressure, used to apply all clutches and bands), is
reduced or "cut-back" in third and fourth gear,
when the direct clutch is applied. This durability problem can be solved by increasing the
quality and quantity of direct clutch plates,
while altering the valve body to eliminate the
line pressure "cut back" in third and forth
gears. The heavy duty direct clutch pack kit
from Transco allows up to seven friction plates
to be fitted to the stock five plate direct clutch
drum. If extra durability is needed, Ford
makes a six-plate heavy-duty direct drum,
used in some 1988 and newer models (Ford
part #E8LY-7F283-A), which will accommodate up to eight friction plates. 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.
Another weakness of the AOD is the
forward clutch, mainly due to difficulties in
downshifting out of overdrive. Shifting into
overdrive requires the overdrive band to engage as the forward clutch disengages. As a
result, a shift out of overdrive (especially
under hard throttle) is difficult for the forward
clutch, because it has to engage under full
power with low line pressure. This causes
undue forward clutch wear and sluggish downshifts out of overdrive. Eliminating the line
pressure "cut-back," (as mentioned, to improve the direct clutch system) and installing
the five plate "police" clutch drum solves
these problems. In addition, enlarging the
forward clutch apply orifice in the valve body
makes the forward clutch engage even faster,
thus, keeping destructive slippage to a minimum. However, it is still advisable to keep the
shifter in (D) during bonsai runs to lock out
overdrive.
After correcting weak links, the important aspect of building a performance transmission is improving shift feel. Stock transmissions are calibrated to shift slowly, resulting in smooth shifts which give the transmission a seamless "luxo-car" feel. While this
may be nice for the average Town Car owner,
it is, unfortunately, a detriment to performance enthusiasts. Mechanical features
unique to the AOD giving it a potential for
driveline snapping shifts unknown to most
other Ford transmissions are left hidden by
this soft calibration. Fortunately, a few simple
valve body revisions (in addition to these
previously mentioned) can prevent those
power wasting "slush shifts." In addition,
these revisions can be done in varying degrees to suit the individual.
The final, but perhaps most important,
valve body revision for a performance AOD is
rasing the shift points. A high-performance
engine cannot develop its full potential if the
transmission shifts in the middle of the
engine's power-band.
With shift points
around 4500
continued on page 26
A-OK AOD
continued from page 24
When changing clutch pack components (i.e.,
clutch drums or clutch packs) clearance is critical. A simple feeler gauge can be used tocheck
clearance as shown. If clearance is not within
shop manual specifications, use another selective snap ring.
Shown are the selective snap rings (foreground) used to set clutch pack clearance and selective thrust
washers (background) used for setting geartrain end play. The selective snap rings are available in
many thicknesses. Consult your Ford dealer for a full listing.
around 4500 rpm (with the high speed governor), the AOD does just that. Since the AOD
uses a throttle valve (TV) cable (with a
regulated pressure limit), instead of the more
familiar vacuum modulator, we cannot adjust
full throttle shift points externally. Instead,
the "TV limit" valve must be modified to provide an increased maximum TV (anti-shift)
pressure to the shift valves. The advantage
of this system is that light-to-moderate throttle
shift points are not disturbed, thus, maintaining the driveability and fuel efficiency of a
stock transmission.
The Motorsport rear lube kit is a necessity for pre-1988 units used in performance
applications. This kit, which requires complete transmission disassembly for installation, re-routes rear lube fluid feeding the
planetary gears, providing more positive lubrication flow. Unlike conventional transmissions, the lube supply to the planetary gears
is critical (especially with low axle ratios and
high speeds) because the planetary gears
are always working in overdrive. Without
adequate lubrication the planetary assembly
could fail, resulting in a very expensive repair
bill. It is best to think of the rear lube kit as
cheap insurance for your AOD.
Upon completing modifications, it was
time for a test flight. After a gentle break-in
run, we were ready to test the AOD's full
potential. The shifts were extremely positive,
chirping second and third. However, at 4900
rpm, the shift points were still a little lower
than our goal of 5500 rpm. Another fine point
was the 1-2 shift, which was actually too
hard (that's a switch) for our application (a
5.0L HO Ranger with a weak 7.5-inch rear
axle). We made a quick trip back into the valve
body and solved these problems, ending up
with an incredible performance transmission, and almost no compromises.
The rear lube kit is just the beginning of
Motorsport's line of AOD upgrades. Many
items are in the works, and soon to be
released. A performance valve body, high
stall speed torque converter, and a deep
sump chrome oil pan are in the works for the
AOD. When these goods become available,
AOD performance will be better than ever.
So stay tuned to WAOD for more information.
If you plan on embarking on your own
AOD adventure, be sure that you study the
proper section in your Ford shop manual very
carefully. Make sure you know what you are
planning to do before you do it, and of course,
if the job looks too involved, enlist the help of
an expert. Further information on the valve
body modifications are available by mail and,
if demand warrants, a complete kit may be
SF
available.
The motivations for our troubles; a suitably tweaked AOD behind the 5.0L HO swapped into this Ranger
pickup will make for one nice little package.
26
SUPER FORD May 1990
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