Hi...new member here. I have an 82 F100 with a new 302 with a lot of mild performance parts on it, such as an Edelbrock carburetor, Edelbrock intake, headers etc. My dad owns a mechanic shop and did this work for a man who about a month later sold the truck to me because he was in a bind for money. I was expecting alot more performance from the truck due to its new motor, but it really isn't as fast as I previously thought it to be. I assume that the C6 with a 2:73 rear has something to do with it so I was wondering about an AOD. I'm hoping that the first three gears in the AOD are lower than the C6, allowing better take off, then of course, the fourth gear to increase my gas mileage. After browsing through this site for awhie, I found somewhere that said that AOD ratios are 2.40, 1.47, 1.00, 0.67 and C6 ratios are: 2.46, 1.46, 1.00. Looks like those first three gears in the AOD are not any lower than the C6, thus, producing no better performance for my truck. Can somebody settle this for me and tell me whether or not ALL AODs are this way? Is there another transmission that would fit on my truck that would achive what I want? Should I just get new ring & pinion along with tranny so a lower rear doesn't kill gas mileage? Someone help please. Sorry so long. --Frank

 

with the 2.73 gears an aod is just a waste unless it is going to be highway only. If you want more off the line and all around driveabilty then put a set of 3.55 or 3.73 gears in it and you will be much happier. If you want to add an over drive tranny you put go up to 4.11's and with the overdrive then you can still get good mileage and have decient take off. With the 3.55 or 3.73 you wouldnt need to change trannys but with the 4.11's i probably would change to an aod.

 

With the 273s and C6, the truck pushes like 2300 rpms when running between 60 and 65. I would like it to run at about 1500 for the gas mileage. So I guess if I were to put 373s in without an overdrive the rpms would be in the area of 3000 rpms (but I'm no expert) which would defenitely improve take-off, but I just can't afford to burn that much gas when cruising 60-65 down the highway, or even worse, 70-80 mph on the interstate. So you're saying you suggest 373s or 411s with AOD? If I were to get 373s or 411s would that just mean get a new ring & pinion set? Or would I have to get whole new axle etc?

 

Actually, you want to run about 2000 rpms for mileage.

You have 2 problems for power, first those gears have to go! Way to high to move a pickup with a 302. Second, a C6, while being brute strong, sucks a lot of power just to make it work. If memory serves me right, the C6 needed near 50 hp just to get momentum out of it. The case was constructed really tough and big, thus will lots of mods and roller bearings, they could get one to work with 14 hp, while actually being even stronger.

The early AOD uses a higher first gear than later models of the od automatic. I believe you can put the 1/2 planetary in the early AOD and gain a lot of low end/off the line power.

I run a stock AOD (1981 with the bad gearing), a 5.0 HO SEFI (90 computer/MAF) with 3.70 gears in the 9 inch. When the motor was fresh I could pull right at 20 on a pure freeway run and roughly 18 combo mileage. The engine is really tired now, so freeway is high 18's, combo is roughly mid 16's.

That is my experience. Even my pickup with 3.25's from the factory was a dog! 2.73's.....gulp!

Kenny

 

So you're suggesting I should???? What should I do?

 

I guess if you can afford it....AOD and 3.70's, but your wallet will dictate what you can do. If you want more "go" and can live with lower milage for a while, change the gears first and drive slower on the highway. You could go to a wrecking yard and pick up a used third member with better gears (pull and save price...roughly $50) and see what it does.

There is really no middle ground between acceleration and mileage....they are pretty much mutually exclusive.

In the perfect, money is no object world, a built AOD with the later gears, 3.70's and you would be very happy! Don't forget, you can lower your effective gearing with shorter tires, so if you need new tires and want it lower overall, shrink the diameter (235/75/15 to a 275/60/15 or even shorter 245/60/15).

It really is up to you.

Kenny

 

Thanks Kenny. My father actually owns a towing company and has a wrecking yard but he's being no help at all in this. He says he should leave it how it is. I actually have 275-60s on there right now (see my gallery). But I do have another question. Could I get the 3.70s by purchasing a ring & pinion set? Or is there more to it? Or should I just go yank a whole other axle out from another truck?

 

You could put 3.70 ring and pinion in it, but it will cost you a shim kit and pinion bearings (3). It isn't the easier job to do either if you have never done it before. I would guess with 3.70's, the C6 and 275/60/15's, you will be turning roughly 3000 rpms at 60 (just so you don't stroke seeing it).

You don't need to swap the whole axle if you have a 9", you can just pull the "pumpkin" center member of the axle (on the 9" it drops out the front, no removeable cover on the backside of the axle). 3.70's stock will be impossible to find, but a nice set of 3.50's should be pretty easy, concentrate on the 4*4's for those.

To drop a pumpkin, you pull the rear wheels, pull the drums off, take out the 4 axle retainer bolts (they also hold on the brake backing plate), and slide the axles out 6 inches to a foot. Then take the driveshaft off, and remove all the nuts around the pumpkin (there are lots, and 2 take a wrench, not a socket). You might have to pry a little, but it should drop out. Be careful, it is heavy, and I do mean "HEAVY". Put a clean towel, board, something underneath it for it to fall on if you can't control it.

To put it in your pickup just reverse the steps.

Your father shouldn't be too traumatized with this simple swap. It would be even better if yours was on a hoist!

Kenny

 

By the way...sweet ride! Mine is a flairside also and I had the same size tires on it forever (I have since dropped it 3"/4" and run 255/45/18's), and is factory bright bittersweet (orange in 1981).

I really like your ride...gear it down! To heck with mileage!

Kenny

 

Thanks alot Kenny. Well it looks like I may have found a set of 3.70s, and the guy said he
had an AOD also. Do you will an AOD stab into my 302? Also, will my driveshaft be interchangeable, or would I have to take the one from the AOD?

 

My 86 150 efi 302 has 355 gears and aod with a shift kit and it moves out pretty well for a stock motor it will smoke the tires when you want and gets 15 to 18 mpg on the highway tach just at or a little under 2000 at 60-65

 

The AOD should be a bolt in except....

You need the tranny gasket (tin between the engine and the bellhousing), get the bellhousing, get the TV rod (some call it the kickdown rod, but it isn't), and I don't know about the AOD's driveshaft. Most of the autos use the same slip yoke (also share them with some manuals), so if you measure your driveline and it is the same, keep your own!

Start with the gears...that is an evening project, maybe a weekend one if you have never done it before. Get a manual and read up on it.

The tranny would also be a weekend project, except...a big except...you have to hook up and adjust the TV rod for the tranny to shift correctly. It isn't hard, but you need the manual and carefully follow the steps. I use the guage method since I changed to SEFI. You carb will need to have the Ford Kickdown linkage setup or it will not work. This part of the project could take longer than the install. You will know if it is adjusted wrong...it either won't shift, shifts late, or shifts so hard your teeth rattle! Also, your shift indicator will be wrong, but you can pull one out of another truck to swap out.

PR(OD)31, compared to your PRD21, minor but it is nice to be right.

As for shift linkage....I don't know if yours is a direct swap...I would think it would be, with possibly only needing the rod that attaches to the tranny.

Good Luck, keep us informed!

Kenny

 

Thanks for all the help. GlennFord, what you're truck has is exactly what I want out of mine. Kenny, that tv rod...not sure what it is. Is it something that's on C6 that I would need to get the one for the AOD, or is that something I don't have at all and I need to get. The funny thing about all this trouble and confusion I'm having is that my dad's been a mechanic since his parents died and he was on his own at 16. So you'd think I'd be a little more knowledgable on these subjects, but he doesn't put forth much effort in teaching me or trying to explain something very thouroughly. But that's pretty much why I seem automobile illiterate. I do have access to his shop though and any work I do will have all the right tools, lifts, jacks, hoists etc. The good thing is that I can get a couple of his mechanics to come help me on the weekends when I figure out what I'm gonna do. Thanks again for everything though. And I'll keep y'all posted.

 

I have an 81 150 with a 302. It orignally had a C6 that went bad. I replaced it with an AOD from an 87 E-150 van. 2 things I learned the hard way. First, the driveshaft slip yoke from the C6 is too big for the AOD. It won't even fit past the rear seal. Paid $12 for my replacement at a upullit salvage yard in Houston, TX. Second, the driveshaft is about 2 to 3 inches too short. Allways measure twice and cut once my dad allways said when he built houses. the same basically goes when you do drivetrain modifications. Due to money problems, i.e.: no money, mytruck has been down for 3 weeks between the slip yoke and too short driveshaft. I will be going to a different upullit tomorrow to try to find an undamaged 81-86 F-150 with a 302-AOD setup. Will post my results here tomorrow nite

 

There is no "TV rod" on an AOD, it's a cable.