This was ganked from an old thread
. It was posted by optikal illushun
and I thought it might be good info for a sticky. If I was ambitious I'd find links and prices to the parts listed and include them....but I'm not.
here it is, direct from my friend who knows his AODs...
AOD - Automatic Overdrive, came in pretty much everything Ford from the mid 1980s to early 1990s. Soft, anemic shifts and low clutch count made this an unpopular choice until recently. Can be rebuilt very nicely to support a fair amount of power or a good unit for some medium towing.
AOD: 1st, 2.40:1...2nd, 1.47:1...3rd, 1:1...4th, 0.67:1.
Now, here comes the rebuild bits. First, extreme positive upshifts are bad on internals. They cause shock loads that can stress then fracture input drums, shafts, and planetaries. Just have your shifts quick and tight, not unreasonablly hard. Also spend an extra $40-60 for a B&M SuperCooler it's a bar and plate design trans cooler that exceedes the tube and fin ones in efficiency by a considerable amount. Heat is the number one killer of transmissions usually caused by slow, soft shifts and trying to overtow with the setup. Also, Dexron III/Mercon ATF is so cheap I recommend changing that crap every 10K mi. Sure it's a little extreme but just drain the pan and refill it. Should set you back no more than $10 with gasket or less if you just drain the pan like I do. I run that cheapass $1.20/qt stuff without a problem in all my vehicles. I don't change that "Filter" too often as it's really just a screen that keeps metal filings from getting into the valve body and plugging it up.
Also, depending on your requrements there are many different frictions available to suit a multitude of needs. For most I'd go with BorgWarner Tans on basic rebuilds, well not basic but low output/low demand. Then for higher performance/high demand consider Alto Red Eagles, BW High Energy, or Raybestos Blue Plate Specials. A RedEagle or High Energy OD band is fine. Kevlar sucks for street use and likes to burn up.
Quality Paper and Rubber kit - Don't skimp on this, just get quality stuff.
TransGo Shift Kit on stock Valve Body - Fixes problems: raises part throttle shift points, boost valve, prevents direct drum burn up, increased fluid flow, etc.
Lentech Valve Body - Does same as TransGo but gives you a 1-2-3/4 shift pattern. Electric OD lockout too. Very trick but not cheap.
WOT Governor calibration (about 5500rpms) - Raises those low 4500rpm WOT shifts, potentially can go higher but will require trial and error to achieve higher speeds...this is on a TransGo VB
. The Lentech can be ordered with any WOT you want but it's about 4 times as expensive.
"A" Overdrive Servo OR Billet Overdrive Servo - Billet is about 10% more capacity than the "A" and 25% more than the "B", the "A" is about 10% over the "B" code. The "C" code sucks, do not use it.
Aluminum 2-3 Accumulator - Better than the plastic one in early AODs
Mechanical diode - In lieu of roller clutch, much stronger.
Billet Outer Input Shaft - Lock-up converter, Support much higher loads, less prone to break
Billet Inner Input Shaft - Lock-up converter - Support much higher loads, less prone to break
Billet 1 piece Input Shaft - Non lock-up converter - Solid is stronger but you gain less economy and higher cruise RPMs, typical tradeoff
2" Overdrive Drum and Band - Greater holding power in Manual 2nd and OD, great for towing.
4R70W internals: 2" OD drum, wide ratio gear set: 2.84:1 1st (15% lower than stock AOD), 1.55:1 2nd (5% lower than stock AOD), and stronger internals. Like going from a 3.55:1 to a 4.10:1 without the gas mileage loss! This upgrade is great as it makes you accelerate faster, hold the OD band easier, and better direct drum. Be warned, if you use a standard VB
with this your shifts will be off...Lentech is the only company that has a VB
specific for the low gear set. The shifts won't be terribly off, maybe 200-400rpms but could be annoying. Just something to consider.
Billet Intermediate Shaft - When used with 4R70W internals. The stock piece is prone to breakage.
Once built, the AOD can hold a fair amount of power. The main problems lie within the valve body (it's awful) and clutch count in the forward and direct clutch pack (int pack isn't really a problem). If you plan to push over 300rwhp go for the billet inner input shaft for sure. Other stuff isn't really needed, just nice to have.