C4 to AOD Transmission Swap (from Dan Jones, m203253@ws2200.mdc.com)

--------------------------------------------------------------------

                        The C4 to AOD Transmission Swap

                                     or

                     How I Spent My 1994 Christmas Vacation

                                by Dan Jones

As promised, I performed the C4 to AOD transmission swap in my parent's 1971

Mustang convertible.  The reason for the transmission swap was to gain the

benefits of the AOD's 0.675:1 overdrive gear (lower cruise RPM, increased MPG,

potentially better acceleration).  The car in question is powered by a mild

302 (600 CFM Holley, dual plane intake, mild cam, dual exhausts) and, before

the swap, had a perfectly good C4 transmission.  While this is essentially a

bolt in job, there are lots of little details that you should be aware of to

make things go smoothly.  These details, in no particular order, include:

                   Procuring the Transmission

                   Extension Housing

                   Converter Compatibility

                   Gear Ratios

                   Working with Aluminum

                   Transmission Jack and Jackstands

                   Transmission Tunnel Clearance

                   Exhaust System Clearance

                   Transmission Crossmember and Insulator

                   Flexplate Diameter and Balance

                   Block Plate

                   Nuts and Bolts

                   Starter

                   Driveshaft and Yoke

                   Mechanical Interlocks

                   Shifter Operation

                   Speedometer Gear

                   Electrical Connections

                   Throttle Valve Operation

                   Hydraulic Fittings

                   Dipstick Tube

                   Drain Plugs

                   Transmission Fluid

                   Shift Kits and Transmission Coolers

To give you an idea of what's involved in a swap like this, I've covered my

experience with each of these details in the paragraphs below.  I've also

listed some comparative weights, dimensions, and gear ratios at the end of

this posting.

Procuring the Transmission

--------------------------

If you're pulling the AOD from a car, getting all of the related stuff

(bolts, electrical connector, dipstick tube, converter, yoke, block plate,

linkages, levers, shifter, hydraulic fittings, etc.), will make life a lot

easier.  However, we used a transmission purchased from a friend of my Dad's

who rebuilds transmissions.  The price was right ($150 rebuilt), but we

had to come up with all the bits and pieces.  Because of the Christmas

holiday, getting all the right pieces was harder than usual, but we managed.

Extension Housing

-----------------

When purchasing your transmission, be aware that there are two tailshaft

lengths used on AOD's.  The short model is the one that is closest to the C4

in overall length.  I forgot to measure it but the SVO catalog says it's 10.1"

long.  The catalog also indicates the short extension housing AOD was used in

all passenger cars except rear wheel drive Lincoln Marks and Continentals (not

sure about the Town Cars), 2WD F-150 trucks built after 11/81, and 83-85 E-150

vans.  Also, don't confuse the AOD with the AOD-E, which uses electronic

control.  There are also extension housing variations among C4's, with a short

tailshaft model (6 5/8") used on some pickups and vans.  Our C4 was the

standard tailshaft model (13 1/8") that was used in most most applications.

Converter Compatibility

-----------------------

The AOD transmission and torque converter are a matched pair.  The AOD uses a

hollow two piece input shaft (one shaft inside the other) for lock-up purposes

and requires a specific torque converter.  This arrangement is used to bypass

the converter torque multiplication in higher gears (60% in third and 100% in

overdrive) for better fuel economy.  This is an attractive feature when using

a high stall speed converter, since locking up the converter eliminates the

excessive slippage (and the attendant heat generation, RPM rise, and increased

fuel consumption) associated with such converters.  On the down-side, the input

shaft is weaker than a similarly sized solid one piece design and you lose the

torque multiplication effect.

Gear Ratios

-----------

The first three gears of the AOD and C4 are of similar ratio.  We were looking

for longer legs and increased fuel economy so we left our rear end gears alone.

If better acceleration is the goal, a ring and pinion swap may be in order.

The beauty of this swap is that the AOD's 0.67:1 overdrive ratio can make a

3.73:1 ring and pinion act like a cruising 2.50:1 ratio.  Come to think of

it, we've got some extra 3.50:1 gears so maybe I can talk Dad into swapping

them in.

Working with Aluminum

---------------------

Like the C6 and C4, the AOD has an aluminum case so use a never-seize

compound on the aluminum threads (e.g. bolting the the insulator to the case).

Also, when working with small aluminum threads (e.g. dropping the pan), I

prefer a beam-type torque wrench so I can tell when I'm approaching the

desired torque value.  I don't trust the click-type wrenches on the little

stuff.

Transmission Jack and Jackstands

--------------------------------

Despite its aluminum case, the AOD is no lightweight.  I measured 150 lbs

(without fluid or converter - as measured on Mom's bathroom scale) for the

tranny and 34 lbs for the converter, so a transmission jack is recommended.

Get the car up in the air as high as possible to give yourself some room to

maneuver.  We used a pair of stacked railroad ties underneath each front tire

and a pair of tall jackstands under the rear axle housing.

Transmission Tunnel Clearance

-----------------------------

The AOD is beefier around the middle than the C4, so it uses up more space

in the transmission tunnel.  Our '71 Mustang was designed to swallow a C6

so there was no problem.  It might be tight on cars with narrow tunnels

(like 65-66 Mustangs), but I'm told they will fit with no problem.

Exhaust System Clearance

------------------------

No problem here on our particular car (dual exhaust without a crossover).

We could have installed the AOD without ever touching the exhaust, but we

decided to unbolt the pipes from the exhaust manifolds for extra working

room.  This will vary from car to car so be prepared for potential exhaust

work.  Since I had the pipes unbolted from the manifolds, I took the

opportunity to put in new exhaust donuts.

Transmission Crossmember and Insulator

--------------------------------------

The only bit of true fabricating that was required for this swap was the

transmission mount crossmember.  While the AOD and C4 overall lengths are

within a half inch of each other, the mounting pad for the insulator on the

AOD is 2 inches farther aft, so the crossmember mounting point needs to be

moved an equal amount.  Whether you need to buy or fabricate a custom cross

member depends on the car you're swapping the transmission into.  On some

full-sized cars, it's supposed to be as easy as switching to a second set of

aft mounting holes.  However, on most of the unibody cars, like Mustangs, a

custom mount is required.  Since I planned to do the swap over Christmas

break, in another state, and was spending someone else's money, I decided to

purchase a custom crossmember, rather than fabricate one.  I purchased it

from Auto Creations, a shop that specializes in overdrive transmission swaps

into older Fords.  Besides the mount, they also sell a throttle valve (TV)

cable kit and can set you up with miscellaneous parts (block plates,

flexplates, etc.), if you can't get them locally.  They also have a list of

cars from which you can pirate the linkages (ones that came with carbs or

throttle body injection and AODs).  Their mount retains the stock insulator,

fit as advertised, and was well made.  They were also very helpful when I ran

into problems with the flexplate, taking measurements for me over the phone.

Even though they were officially closed over the holidays, they stayed in

phone contact with me to make sure things worked out.  If you're contemplating

this swap, I suggest you give these guys a call.  I've included their number

and address towards the end.

Flexplate Diameter and Balance

------------------------------

One of the more important parts of the swap is to choose the proper flexplate

for your application.  The integral bellhousing AOD requires a flexplate with

164 teeth (approximately 14 1/4" diameter with an 11 7/16" torque converter

bolt pattern) for proper starter placement and converter compatibility.  The

C4, however, uses a detachable bellhousing that is matched to one of three

different flexplate sizes (148, 157, and 164 teeth).  The 148 teeth flexplates

are comparatively rare, having been used in cars like the V8 Mustang II.  The

157 teeth flexplates were generally used in 289/302 small and mid-sized cars,

while the 164 teeth flexplates were used in 289/302 full-size cars and

351W/351C applications.  The C4 164 teeth flexplates and the AOD 164 teeth

flexplates will physically interchange, but there are two balance weights

(pre-'81 302's use a 28.2 oz-in balance weight, '81-up 5.0 HO's are 50 oz-in),

to be concerned with.  I haven't had a chance to verify but I think all 351W's

and 351C's used 28.2 oz-in balance factors.  Also, the catalog I looked at

suggested that 1981 and up non-HO 302's are still 28.2 oz-in (at least to

1990).  Anyone know for sure?  In my case, the flexplate in the 1971 Mustang

came with 157 teeth and a 28.2 oz-in balance factor, so it required replacing.

Since they both have 164 teeth and 28.2 oz-in balance factors, I was under the

impression that flexplates from either a 351W w/AOD or early 289/302 w/C4 from

a full-size car would work.  Looking through the books at the parts store

showed that these were not common part numbers, and listed the 351W part as

working with an AOT, not AOD, transmission.  Not knowing if the AOT indicated

a subtle variation that I was unaware of, I decided to order the early

289/302/C4/full-size part (OEM D1AZ-6375-A, Saginaw XF15).  This turned out to

be a mistake.  When we put the converter and transmission up to the engine for

a fit check, the modeling clay we had put in the crank pilot showed the

converter snout was barely making contact.  Apparently there is a difference

in flexplate depth.  It all would have bolted together and the starter may

have even managed to reach the flexplate teeth, but there would have been no

support for the converter and the starter would have eventually chewed up the

flexplate.  Procuring a 351W/AOD flexplate over the holidays turned out to be

an ordeal (dealers wanted 14 days), but it was required for proper converter

snout to crank pilot placement, while retaining the proper diameter and

balance.  We finally found a transmission supply house that had the right

piece.  We put the 351W/AOD next to the early 289/302/C4/164 teeth part and

there was a difference in height.  Since then I have checked some aftermarket

catalogs and they show the same part number for both applications, so buyer

beware.  The part we finally obtained was from Sealed Power and corresponded

to OEM E0AZ-6375-A (164 teeth flexplate, 28.2 oz-in balance factor, 351W

with AOD applications).  If you're swapping an AOD onto an '81 or later 5.0,

you'll need the AOD flexplate (164 teeth, 50.0 oz-in balance factor, for 5.0

with AOD applications).  I think the OEM part number for the late 5.0/AOD

is E2AZ-6375-A, but I didn't verify this.  In a pinch, you could swap (weld)

balance weights between flexplates to get the proper balance factor.  If you

choose to do this, remember that the balance factor is a moment of inertia

(distance time mass) so keep the product of the distance from the weight to

the center of the flexplate and the balance weight (plus any additional weld

weight) equal to a constant (either 28.2 or 50.0 oz-in).

Block Plate

-----------

A block plate (the thin stamped sheet metal plate that fits between the engine

block and transmission housing) which matches the large AOD bellhousing is

also required.  This plate provides the correct starter location and engagement

depth for the torque converter snout in the crank pilot (assuming you have the

right flexplate).  We used one from an early 289 full-size application (C4

with the large bellhousing).

Nuts and Bolts

--------------

The bosses on the AOD bellhousing are thicker than those of the C4, so longer

bolts are required.  We didn't have enough of the proper length (2 1/8 to

2 1/4" long bolts), so we cut down a few longer bolts to get the desired

number of threads.  Use a stiff piece of wire as a gauge to make sure they

don't bottom out.  You can re-use the C4 torque converter nuts on the AOD

converter but it's a good idea to use new ones since these tend to round off.

Also be aware that the AOD is a mixed standard transmission, despite what the

METRIC embossed into the pan may imply.  Some bolts are metric, others are not.

Generally, the tranny internals are metric, but the places where the tranny

connects to the car (insulator, hydraulic fittings, speedo-drive, etc.) are

not.

Starter

-------

The original starter was retained and aligned properly.

Driveshaft and Yoke

-------------------

When we first put the the yoke into the tranny, it appeared we would need to

shorten the driveshaft by an inch or so.  This was unexpected since the AOD

is only a 1/2 inch longer than the C4.  Upon closer investigation, it became

apparent the yoke was the problem.  We had to trim the C4 yoke to get it to

fit properly.  The AOD yokes must be a bit shorter, so pick one up if you can.

Mechanical Interlocks

---------------------

The '71 Mustang has a mechanical interlock which locks the shifter into park

whenever the ignition key is in the lock position.  I'm not sure what year

this first appeared on Fords, but I know my '66 doesn't have it.  You could

bypass the interlock but we kept it functional.  This required removing the

TV/shifter shaft assembly from the AOD (involves dropping the pan and filter).

Using the original C4 lever as a guide, we cut a spare lever and welded it on

the shaft.  This caused a problem since we were unable to remove the small

circular grommet that seals the end of the concentric cylinders of the

TV/shifter shaft assembly without damaging it.  The C4 has a rubber O-ring

in this area but the AOD uses a special formed piece which, like the flexplate,

wasn't easy to find over the holidays ("Sure we've got one but you'll have to

buy the $119 rebuild kit to get it").

Shifter Operation

-----------------

We retained the C4 floor mounted shifter in the Mustang.  Eyeballing the AOD

and C4 shift levers, it looked like the hole in the AOD shift lever would need

to be moved a bit so we welded up hole and drilled a new one.  Once everything

was assembled, we adjusted the linkage to get proper engagement of the gears

and interlocks, but the pointer was off.  It turns out the hole was probably

in the right spot to begin with.  I believe there is a quite a bit of

variation in Ford shift levers (especially between floor and column mounted

shifters, but also between body styles), so this will need to be checked on a

case by case basis.

Speedometer Gear

----------------

The speedometer driven gear assembly from the '71, including bolt and retaining

clip, slipped right into the AOD.  I didn't get a chance to verify the ratios,

but the speedometer operated normally.  There may be some variation (seven and

eight teeth gears?) with the AOD drive gear (the gear inside the tailshaft

housing), so you may have to change driven gears for proper calibration.

Electrical Connections

----------------------

The AOD uses a four pin electrical connector for the reverse/backup lamps and

neutral sensing switch.  We didn't get one with our tranny, so we soldered

some wires on and used a liquid rubber compound to insulate.  If you end up

soldering, be careful not to melt the plastic housing that holds the pins in

place.

Throttle Valve Operation

------------------------

The AOD does not use engine vacuum and a modulator valve to sense load.

Instead, a throttle valve is used which moves proportional to throttle pedal

travel.  Unlike a kick-down rod, the TV linkage has to operate throughout the

full travel.  This is one of the most important parts of the swap to get

right.  Failure to do so will cause poor shift quality and can ruin the

transmission.  When adjusting the linkage, it is safer to err on the side of

hard shifts.  There are a several ways of implementing the TV linkage.  A rod

arrangement was used on AOD cars equipped with carbs and TBI while a cable was

used on SEFI cars.  We were planning on getting the linkage off a variable

venturi (VV) carb from a local junkyard that had a stack of them, but they

had recently tossed them all out.  We ended up adapting the kick down rod to

serve as the TV linkage.  The trick is to ensure the proper range of travel of

the transmission TV lever for the entire carburetor throttle range.  We had

another AOD equipped car to look at to get the proper lever orientation and

ratios.  You also need a way to adjust the linkage to vary shift feel.

Alternatively, you could adapt a TV cable from an EFI application or purchase

one of Auto Creation's TV cable kits.  For more information on alternatives, I

suggest you get a copy of the May 1990 issue of Super Ford magazine. The

article "A-OK AOD" contains a sidebar on adapting the AOD to non-stock

applications.  Ignore the part about your stock flexplate and block plate

working just fine and pay close attention to the linkage descriptions.

Hydraulic Fittings

------------------

The hydraulic fittings on our AOD were larger than those of the previous C4.

After the existing lines were trimmed to their proper length, two adapter

fittings (1/4" (ID) pipe, 5/16" (OD) tubing) were used to mate the fittings

on the transmission lines to the AOD case.  I believe the lines on our car

were not original since they looked like new and had quite a bit of excess

length.  They were also harder than any factory line I've dealt with.  Even

though we used the proper tubing benders and double flair tools, the lines

were very hard to work with.

Dipstick Tube

-------------

With a minor bending of the the attachment bracket, the AOD dipstick tube went

in easily.  The AOD tube proved to be shorter than the C4 tube and ended up in

close proximity to the export brace, so a long neck funnel was required to fill

the transmission.  Of course, this will vary from car to car.

Drain Plugs

-----------

One thing I forgot to do was to install a drain plug kit when I had the pan

off.  B&M makes an inexpensive kit that, along with our stock converter's

drain plug, would make it very easy to do complete fluid changes.

Transmission Fluid

------------------

AOD's take a lot of Dextron-II transmission fluid (the C4 used type F).  The

Chilton's we checked for capacities quoted 24 pints (12 quarts) for a totally

dry transmission like ours.

Shift Kits and Transmission Coolers

-----------------------------------

This particular car is not subjected to much abuse so we didn't install a

shift kit or auxiliary transmission cooler.  To begin with, we'll simply

adjust the TV linkage to give firmer shifts and see how it works out.

For performance applications, the guys at Auto Creations recommend a Karl

Baumann shift kit and the Thunderbird C-servo upgrade.  Because we might be

putting an AOD behind my brother's 351W and a friend's 351C-2V, I did some

research on AOD durability and performance modifications.  There are several

things that should be done to an AOD, if you want it to live behind a high

performance engine.  It may be several weeks before I can get to it, but I'll

try to post a summary of my findings.

Unfortunately, I haven't had a chance to drive the car yet, since I had to get

back to St. Louis.  I left the car up on jackstands, with the wheels spinning

in all gears.  I'll get some time behind the wheel the next time I'm in Ohio.

While there are lots of little details (and a couple major ones), this is

definitely a do-able swap, especially if you get all the related parts from

the same car.  I've included all the variations that I am aware of, but

remember YMMV.  As a reference, I've included some comparative C4 and AOD

dimensions and weights, plus a bunch of gear ratios.  Email me with any

corrections or additions you may have.  Also, before I sign off, allow me to

thank all of you who responded to my request for AOD information.

                                                   Cheers,

                                                   Dan Jones

                                                   m203253@ws2200.mdc.com

P.S.

I'm going to send a copy of this posting to Auto Creations and ask them for

any input they might have.  I'll post any additional info at a later date.

Based upon my positive experience with them, I'm going to work with them on

a couple of other swaps in the future.  When I mentioned I was going to post

this write-up to the list, they said they'd give me a break on prices for any

referrals so tell Dave I sent you.  They can be contacted at:

                           Auto Creations

                           19201 Meadowvale Rd.

                           Elk River, Mn 55330

                           (612) 441-5567

C4 and AOD Dimensions

---------------------

Overall Length (bellhousing to tailshaft housing end, flat-to-flat):

 AOD - 30 3/4"

 C4 - 30 1/4"

Notes:

 "Engine Swapping Tips and Techniques" lists C4 length as 27 3/4" (C6 length

 28 1/2" or 28 3/4").  I may have measured to the end of the output shaft,

 not to the end of the tailshaft housing.

Distance from Bellhousing to Insulator Mount (flat to mounting hole centerline):

 AOD - 21 3/4"

 C4 - 19 3/4"

Torque Converter Stud Spacing (centerline-to-centerline)

 AOD/C4/164 teeth flexplate - 8 1/4" between closest studs, 11 7/16" between

 farthest studs (stud pattern diameter)

 C4/157 teeth flexplate - 7 3/4" between closest studs, 10 5/8" between

 farthest studs (stud pattern diameter)

Transmission Lengths from "The E4OD", Ford High Performance, April 1995

Trans  Bellhousing    Overall Length

       Face to Trans  From Bellhousing

       Mount Length   To Tailshaft End

C4       20 1/4"         30 1/2"

C6       22 1/2"         33 1/2"

AOD      22 1/4"         30 3/4"

E4OD     29 3/8"         37 1/2"

Torque Converter Snout Diameter (from early SVO catalog)

 289, 302, 351W/C/M, 400, 429/460 - 1.375"

 FE series and early '68 Lincoln 460's - 1.848"

Flexplate Diameters

 164 teeth - 14 3/16" (13" converter)

 157 teeth - 13 1/4" (11" converter)

 148 teeth - ?

C4 Variations

-------------

 Large bellhousing - smooth flair case, twin bolt circles (case to housing,

 outer secures bellhousing to trans case, inner secures oil pump to case),

 3 locating tabs, 14 3/16" flexplate, 13" converter, no dipstick hole in

 main case (dipstick goes into right front corner of pan), used in small-block

 powered large cars and light trucks.

 Small bellhousing - step case, single seven bolt circle (case to housing),

 13 1/4" flex plate, 11" torque converter, dipstick hole in case (seals with

 an O-ring), five bolt ('64 1/2 and early '65 Mustangs, etc.) and six bolt

 versions, used in small and medium small-block powered cars.

 Trans-Dapt supposedly makes adapters for six bolt blocks to five bolt

 transmissions (need to check on details).

 Top bellhousing bolt holes are 5 1/8" apart.

 "C" intermediate servo (289 hipo applications) is largest but rare.

 "H" servo is next largest, used on 302 4V engnes from 1968.

 "A" servo is typical stock unit.

 Pinto govenor allows highest rpm shifts, p/n D7ZZ-7C063-C.

 C5 pan interchanges with C4 and is deeper.

 There was a revision in mid '70's to nine mounting bolts for the valve body,

 previously used 8 bolts.

 Main cases and bellhousings for large and small versions are not

 interchangeable.  5 and 6 bolt small bellhousings are interchangeable between

 each other (on the case side).

 Entire 6 bolt (small or large bellhousings) transmissions, except for

 dipstick locations, are interchangeable in many cars (some smaller cars

 require the small bellhousing variant).

 C5 bellhousing looks similar, but has a completely round hole in the front

 pump area and is not interchangeable with C4 bellhousing.

 Standard Tailshaft - 13 1/8" long, most applications.

 Short Tailshaft - 6 5/8" long, some pickups and vans.

 Input Shaft Spline Count (8 cylinder and some 6 cylinder applications)

  '70 and later - 26 splines

  pre-'70 - 24 splines

 Note: Some 1970 input shafts have 26 splines on both ends ('71 and later have

 24 splines on one end and 26 on the other), making them the most desirable

 for drag racing applications.

 Need to add C4 valve body variations (green-dot, cruise-o-matic, etc.) and

 AOD shift sequence

 Four and six cylinder versions are light duty (fewer clutch plates).

 Some C4's (late '60s, early 70's Mavericks? need to check details) had

 full-manual valve bodies.

Transmission Weights

--------------------

 AOD (without converter or fluid) - 150 lbs

 AOD stock torque converter - 34 lbs

 C4 (without converter or fluid) - 110 lbs

 C4 torque converter - ? lbs

 C6 (without converter or fluid) - 140 lbs

 C6 torque converter - 30 lbs small block, 31 lbs big block

 FMX (without torque converter, unknown fluid level) - 160 lbs

 FMX torque conveter - 32 lbs

 Ford-o-Matic (pre-FMX), cast iron case - 228 lbs

Notes:

 - AOD and C4 weights are as measured by me using a standard bathroom scale.

 - FMX and C6 torque converter weights provided by Steve Grossen (also used

   bathroom scale).

 - Ford-o-Matic weight is an assembly line weight provided by my Dad.

 - C6 weight is from "Engine Swapping Tips and Techniques" which also lists

   the C4 at 109 lbs.

Transmission Ratios Comparison

------------------------------

     Stock  Stock  WR     1983   1984   85-89  90/SR  WC     TR     TR

     C4     AOD    AOD    T5     T5     T5     T5     T5     3550   3750S

1st  2.46   2.40   2.84   2.95   2.95   3.35   3.35   2.95   3.27   3.18

2nd  1.47   1.47   1.55   1.94   1.94   1.93   1.99   1.94   1.99   2.06

3rd  1.00   1.00   1.00   1.34   1.34   1.29   1.33   1.34   1.34   1.39

4th  ----   0.67   0.70   1.00   1.00   1.00   1.00   1.00   1.00   1.00

5th  ----   ----   ----   0.73   0.63   0.68   0.68   0.63   0.68   0.65

     WR     CR     SROD   SROD   BW     BW     RG     RG     RG     BW

     TL     TL     alum   cast   T10L   T10M   4+1    ROD    ROD    T56

1st  2.78   2.32   3.29   3.07   2.36   2.36   3.27   3.27   3.01   2.97

2nd  1.93   1.69   1.84   1.72   1.76   1.62   2.13   2.13   1.88   1.94

3rd  1.36   1.29   1.00   1.00   1.41   1.20   1.57   1.57   1.46   1.35

4th  1.00   1.00   0.81   0.70   1.00   1.00   1.23   1.23   1.19   1.00

5th  ----   ----   ----   ----   ----   ----   1.00   1.00   1.00   0.82

6th  ----   ----   ----   ----   ----   ----   ----   0.76   0.62   0.62

     1984   85-86

     SVO T5 SVO T5

1st  4.30   3.50

2nd  2.37   2.14

3rd  1.50   1.36

4th  1.00   1.00

5th  0.76   0.78

rear 3.45   3.73

Notes:

 - C4 ratios are from the 1966 Mustang Illustrated Facts Book which also shows

   a 1.46 2nd gear ratio for certain transmissions.

 - AOD overdrive ratio is sometimes listed as 0.675:1.

 - WR AOD indicates an AOD with the wide ratio gear set from SVO Motorsports.

 - Some 1985 T5's used 1984 gear ratios (carry over production).

 - Certain 1989 T5's used 1990/SR gear ratios.

 - SR T5 indicates Ford service replacement transmission for '85-up 3.35 box.

 - WC T5 indicates SVO Motorsports World Class T5 (M-7003-CA, E4ZM-7003-A).

 - All T5 ratios from Muscle Mustangs and Fast Ford, June 1991, "Mission:

   Transmission".

 - When comparing ratios from automatic and manual transmissions, the torque

   multiplication of the torque converter must also be considered.

 - The AOD provides 60% lock-up in third gear and 100% lock-up in fourth gear

   (eliminates torque multiplication).

 - SROD indicates single rail overdrive.

 - T10 and SROD ratios from "Engine Swapping Tips and Techniques".

 - SROD aluminum case gear ratios are for a 1979 302 V8 application.

 - SROD cast iron case gear ratios are for 77-78 V8 Granada applications.

 - WR TL indicates wide ratio top loader.

 - CR TL indicates close ratio top loader.

 - BW T10 indicates Borg Warner T10 used in some Fords.

 - TR 3550 indicates the 5 speed overdrive Tremec transmission.  The TR-3750S

   is a proposed close ratio version (no confirmation if it has been produced).

   There is also a TR-4250 version which has the same ratios as the TR-3550.

 - Tremec information taken from the September 1992 Super Ford article "Top

   Loader Plus One".

 - RG 4+1 indicates the Richmond Gear non-overdrive 5 speed transmission

   (formerly produced by Doug Nash).

 - RG ROD indicates the Richmond Gear overdrive 6 speed transmission.

 - Some RG transmissions are available with alternative (3.27/2.14, 4.06/2.22

   4.41/2.22) first and second gear ratios.

 - Richmond Gear information taken from JBA and Summit Racing catalogs.

 - T56 ratios are for the Ford aftermarket version.  The GM and Chrysler

   versions have different ratios.

 - All gear ratios are for Ford versions of the particular transmissions.

Balance Factor Information

--------------------------

1981-and-up 5.0 HO - 50.0 oz-in

1981-and-up 302 (non-5.0 HO) - ?

Pre-1981 289/302 - 28.2 oz-in

351W and 351C-400 - 28.2 oz-in