AOD in classic 67 mustang

Hey There,

I found this in another forum, hopefully it will let you know what you are up against. Have you bought your AOD already, if not then try to get a later year one (1989+) as there was a problem with the 3rd gear not getting enough lube in the earlier ones. I bought one out of an 1990 mustang for that very reason, I'll drop it in my 1968 coupe someday.





C-4 to AOD conversion

for hot street or high power engine, consider late model V6 4R70W with minor mods & electric control box. See info below.
302 HO's have different - 50 oz - balance weight on flexplate:
early & non-HO 302s & all 351's have 28 oz
Alternate to AOD is put Gear Vendors overdrive box behind C-4. Probably a little more expensive.
AOD type trans bigger than C-4 but usually still fits in trans tunnel in early mustang etc
Parts to get from AOD or /E or 4R70W donor car:
all bolts including eng to trans, they're longer for AOD than for C-4
electrical connector plug(s) and some wire - just reverse light and neutral safety switch on plain AOD

dipstick & tube
torque converter & mounting bolts
trans yoke, C-4 yoke is a little longer & has to be trimmed to use with stock driveshaft.
Can use stock C-4 driveshaft with AOD & AOD yoke.
4R output shafts same dia but some 4R housings have larger bushing
so larger OD yoke, 4R yoke has same U joints.
block plate, between bellhousing & engine, also lower shield for torque converter & shield bolts
all linkage & levers. For plain AOD on carb car, get carb throttle valve linkage from car or light truck with AOD & carb.
See TCI website for instructions on adjusting.
for efi engine, get throttle valve cable and brackets.
ABSOLUTELY Use new plastic bushing in throttle body arm , or replace with brass bushing available from Ford and aftermarket trans shops
Need to know if existing bushing was black or yellow, $2.50+ at ford dealer. If bushing breaks, ruins trans almost immediately
absolute MUST to correctly adjust throttle valve (rod or cable) see www.baumannengineering.com or www.tccoa.com their tech articles,
or the TCI website

Get both hydraulic fittings and some line from right side of trans (cooler lines). AOD lines are bigger than C-4 lines, use 1/4" ID pipe to 5/16" OD tubing straight adapter fittings to adapt AOD to C-4 lines

the AOD rear mount bolts are exactly 2" farther back than the C-4.
See www.windsor-fox.com, or npdlink.com (catalogue) for
modified mount, or picture for how-to if you can weld and want to make your own. (or also see www.ronmorrisperformance.com)

C-4 speedo drive gear on cable fits AOD, check ratios donor & your car to get right speedo drive gear.

AOD speedo drive gear on tailshaft is machined into tailshaft, usually don't have to change unless going deeper than 3:54, change cable gear

C-4 starter should work. Big car C-4 is 164 teeth flywheel.
AOD is 164 teeth flywheel. C-4 intermed car flywheel is 157 teeth.

some C-4 shifters (I.e. older Mustang) hook right up to plain AOD
shift linkage, sometimes minor hole relocation needed

flexplate (flywheel) all 351W have 28.8 oz balance weight with 164 teeth, but do NOT use flywheel from 302 full size car with C-4,
D1AZ-6375-A, is 164 teeth but depth maybe not right and AOD converter snout might not contact and might not be supported
Need 28.8 oz weight flywheel from 351W with AOD & 164 teeth, EOAZ-6375-A. Available Ford & aftermarket.
5.0 liter HO motor uses larger 50 oz weight, don't use with early non-HO 302 or with 351, big imbalance. They take 28 oz flywheels

AOD holds 12 quarts with converter dry, use Mercon or, better, Mercon V

anti-sieze all bolts going into aluminum. First clean bolts & holes with solvent or carb spray, then air blow dry, use loc-tite on
pan bolts & torque, will not vibrate loose & leak. Get trans pan drain plug, put near bottom on rear of pan, easy drain.

Some C-4 info:
standard C-4 tailshaft 13-1/8" long,
some light trucks had short 6-5/8" tailshaft"
C intermediate servo largest, rare, 289 hi-po only
H int servo medium, 302 4bbl, 1968 & newer
A int servo smallest, standard on most C-4's
(small 2bbl V-8's, probably also 6 & 4 cyl?)
pinto governor D7ZZ-7063-C for C-4 highest full throttle shifts
(of stock Ford governors) maybe D7ZZ-7C063-C ?
some late 60's, maybe early 70's Mavericks C-4's had full manual valve bodies

C-4's in full size cars had larger bellhousing with 164 teeth flywheel, intermediate cars smaller housing w/157 teeth flywheel
C-4 takes about 15 hp to turn, AOD takes about 27 hp (another source says 57hp - sounds excessive)

Ford trans weight comparison
weight, trans dry, without converter
AOD C-4 C-6 FMX Ford-O-matic (before FMX, cast iron case)
150 110 140 160 228


Ratios 1st 2nd 3rd OD
AOD 2.40 1.47 1.00 0.67
AOD wide ratio 2.84 1.55 1.00 0.70
C-4 2.46 ? 1.00 n/a

AOD has 60% lock-up in 3rd & 100% in OD/4th which eliminates converter torque multiplication both gears, can delete but then lose lockup
altogether which hurts mileage and top gear acceleration due to
converter slip

see www.baumannengineering.com for info, also www.artcarr.com and Precision at www.converter.com
some good overhaul info on www.transonline.com
for higher stall converter, MUST get good quality converter or you lose torque multiplication
now, new info has it that stock V6 AOD converters have higher stall speed, work with moderate motor mods

some good ones - Art Carr (I paid $350, they tailor to your engine & application and can re-do later)
Precision is about $300 for lock-up, also check Lentech & Baumann, & www.levelten.com, & Edge are now becoming popular
www.windsor-fox has some adapter stuff, such as modified trans mount, good picture on their website, also good efi retrofit info & parts
also see www.ronmorrisperformance.com for retrofit efi, incl onto non-efi motors, & parts
AOD 88 & up from HO 5.0 liter generally stronger.
Pre-88 AOD's don't have good rear geartrain lube, DON'T GET!
92-93 F & E trucks AOD have wide ratio, A od servo & 2" wide od band, but probably longer 3/4" output housing
these are strongest plain AOD, if long housing it can be swapped
AOD's from Lincoln Mk VII LSC's also heavier duty, have 6 instead of 5 plates in direct (3rd gear) drum, but longer tailshaft
standard tailshaft housings marked F2TP or EOAP.
Longer housings marked EOTP or EOLP

92 & newer car AOD uses 6 clutch direct drum also

do not use stock AOD from V6 or smaller, - has fewer clutch plates in direct drum (can add more) & smallest od servo (can change)
A servo biggest, B servo most common like in 5.0 HO Mustangs and V-8 cars & pickup's, smallest C servo in V-6 cars
servo easily changed, under valve body, trans does not have to come apart.
Can NOT change od band, or add clutch plates, or change to wide ratio without taking trans apart.
Need wide ratio set or upgrade kit from Baumann for wide od band
92 AOD from 5.0 HO Mustang best common car AOD, have B od servo and 6 clutch plates in direct drum, stock length tailshaft
AOD's 93 & up cars are AOD/E and require electronic control instead of having throttle valve rod or cable. Stock is hooked to main computer, stand-alone control available Baumann $400, is better than stock

94-95 T-Bird AOD/E's have Dynax hd clutches and wide ratio & 2" od band. (so 94-95 T-bird AOD/E's are best /E's - wide ratio, dynax hd clutches)

Ford wide ratio kit has 4 intermediate clutches in it instead of normal AOD 3 clutches. The T-bird /e's have all those parts except for the 4th friction. Can be added - get intermed press plate F3L4-7B066-A
is stamped "4 plate"

Could also add "mechanical diode" which increases durability in the intermediate/2nd gear clutch, is also in Ford /E wide ratio kit, comes standard only in 99 & later 4R70W's. Quite expensive as upgrade kit.

V6 trans have same bellhousing as Windsor V8's so any /E or 4R70W behind V6 will fit 302/351. 4.2 V6 4R70W 99-up best electronic AOD
standard length AOD w/AOD yoke can generally use existing C-4 driveshaft, driveshaft has to be shortened to use longer AOD housing
Standard housing can be swapped for longer housing

96 & later 4R's all wide ratio. 3.8 V6 /E's only 1 less direct clutch disc than V8 /E's so can be easily upgraded, 4.2 V6 4R70W trans has same # clutches as V8 & bolts behind Windsor V8. 98 or 99 & newer
have best internal parts.

If overhaul AOD, recommend Art Carr or Alto premium rebuild kit.
Has high perf "red" direct clutch friction plates, all new bushings,
all new needle bearings, treated direct clutch steel plates (helps prevent overheating and warping) instead of buying separate
Has extra dirct clutch plates so you can add for more durability.
Cast direct drum will hold up to 6, plenty good for even hp.
However, need to check input splines for wear in cast drum.
See Baumann site for info and pictures.

street, stamped steel drum like in AOD/E's can be swapped into AOD & holds up to 8 plates, hi hp only, costs $100, takes different plates. If you DO replace cast drum with steel, have to make sure to substitute the different clutch plates when you get overhaul kit. Baumann shift kit firms up 3rd shift, so 6 plates OK for all except pretty high horsepower and/or lots of abuse.

Also recommend Art Carr hd od band (unless upgrading for 2" wide band, Baumann has kit for 2" wide band in AOD), do NOT use other mfg Kevlar band, can glaze, and get Carr or Ford A od servo. OD servo & accumulators go in under valve body, trans doesn't have to come out or apart

Recommend Carr "zero leak" or 98 up Ford molded rubber 2-3 accumulator, this also firms up 3rd gear shift. stock accum often leaks reducing shift pressure - also recommend Ford 98 up rubber 1-2 accumulator.

2-3 accumulator & A od servo about $30 ea, helps 2 major AOD weak points. Hd OD band also about $30, but trans has to come apart,
not critical if good shift kit & 2-3 accumulator. Just don't full throttle into od. Let off when shifting into od.

whichever AOD shift kit, need to eliminate "cutback" which is reduction in internal line pressure for 2 to 3 and 3 to od shift to make smooth
this, however, allows slippage, generates heat, reduces durability. Baumann kit & others have cutback elimination - CHECK!

for any heavy duty use, & for high stall converter, good trans cooler VERY important! AOD's very susceptible to heat damage.

Recommend synthetic fluid like Mobil 1, or newer Mercon V, or at least change fluid quite often, easy with pan drain plug

Lentech valve body changes operational sequence, eliminates partial lockup in 3rd, has electric control for od, reduces heat buildup, uses stronger 2nd gear clutches for 3rd gear eliminating weak direct clutch problem (if I read their info right - CHECK!)

all above said, good model stock AOD with above minor improvements can still be good trans for moderate power increase

Instead of rebuilding AOD and adding major upgrades, maybe no more expensive to go good used 4R70W proper model (99-UP 4.2 V6 4R70W best that will bolt to Windsor V8, has all the good Ford heavy duty
mods, and same clutch packs etc as the mod motor V8 trans)
and get $400 control box, about same bottom line and much better trans with just minor tweaks.

by all means, read and re-read info on baumann website and ESPECIALLY on www.tccoa.com, tech articles, trans 101.

Also check collection of detailed AOD, AOD/E and 4R70W info on
www.lincolnsonline.com, in their tech articles, under transmission.
"RWD Ford OD automatic parts interchange". Tells which later model
heavier duty parts fit into earlier like AOD.

FYI for good inexpensive electronic ignition to replace points -
ford Duraspark II, get from same size engine so distrib fits,
see how-to & wire diagram at //members.boardhost.com/MustangSteve
is electronic but not computer control - I got for $30 @ junkyard
Get control box with blue strain relief (correct version), coil, all wiring between components, 4 pin & 2 pin (power in) connectors