I have a 84 F150 which I'm lookin for a Transmission for, I found a c6 online. Wondering what are the advantages of the different types. Is the c6 a good choice?

 

c6 is a tough transmission. But it has only 3 speeds with no overdrive and no lock-up convertor, so it's a bit of a gas hog.

An AOD has overdrive and a lock-up convertor so it's good on gas. But in stock form it's not that great for heavy duty use(towing) and the control cable adjustment is touchy.

E4OD has a lock-up convertor and overdrive, and is a pretty tough transmission, really tough if it's up dated to 95+ specs when it's rebuilt. But it's a fully electronic transmission, so it needs a computer to run it. They make stand alone computers for about $500-$1000 to make it work on a older truck.

 

My 84 has the AOD. Once I got the linkage adjusted properly, it's been great. I haven't done any towing, but I've hauled 1500+ lbs in the bed, with no problems from the trans.
I have a 97 F350, with the E40D. It ended up overheating a while back, not too many local shops wanted to touch it. Ended up buying a rebuilt on line.

 

The AOD is perfectly fine for towing as long as the user doesn't tow in the Overdrive (OD) gear. For towing duties, use the Drive (D) gear instead. Ford clearly explains this is the owner's manual. Ignoring this warning is what has destroyed many AODs and is one reason why the AOD has unfairly gotten the reputation of being "weak."

The other reason is when the AOD has an incorrect throttle valve adjustment. Unlike the kickdown rod on a C6, the AOD uses a TV rod or TV cable to control transmission line pressure. And like Franklin said, it IS touchy. It needs to be set correctly for the AOD to have a long life. The TV rod or TV cable is basically a mechanical throttle position sensor that MUST be connected and it MUST follow the entire travel of the throttle lever to properly "ramp up" the line pressure as the throttle is increased.

As long as these two are in order, an AOD is a great transmission that will last a LONG time and give great service!

That being said, if you have a Heavy-Duty F250 with big axles and large displacement engine that is made for towing extremely heavy loads all the time, the C6 is a stronger, heavier-duty transmission that is stupid simple and will take tons of abuse. If you have a light-duty F150 with a small block engine that is on the highway most of the time but does have occasional towing duties, the AOD is perfectly capable and will get MUCH better gas mileage than the C6.

Capiche?

 

You mentioned a C6 which is an automatic trans, so everyone is assuming you want an auto. If manuals are in the running too let us know and you can get advice on them as well.

 

I'm not really sure which trans was originally in the truck, but it did have an overdrive gear so I'm guessing it was the AOD. I won't be doing much towing other than a few hundred pounds on the bed. I've juiced up my 302 quite a bit, and I drive it like a sports car, on top of that I'm putting some 35s on it so I'm looking for a trans that'll keep up and not give out after a few months like this one did.

 

What gear ratio do your differentials have? You are not going to be happy with this truck with a 302 and 35 inch tires on it without a gear change. Your AOD and hopped up 302 would be happier if you had 4.10 gears. Figure out where your engine makes it's most power and torque(at what rpm) and figure out what rpm you will be turning at road speed, and it will tell you what gear you need to run with 35's. Some of the guys on here are good at that and know where you can get calculators to figure it out.

You might as well do this logically so you are happy with the truck afterward. Having to downshift going up a hill on the interstate doing 65mph is not much fun and believe me it will happen if you don't do some figuring.

 

Franklin is right again.

4.10 is the minimum gear you need. With 35" tires, I think you need to go even deeper than that.

 

I agree, I would go with 4.56s for highway driving or 5.13s if you stay mostly on gravel and country roads

 

Not sure about the gears, I'm assuming its still the stock gears. I was planning on going with the 4:10 ratio eventually! I'm trying to figure which combination would produce better power and overall driveability. My truck is pretty evenly split between highway and city, probably leaning more towards highway miles tho.

 

Is your transmission you have in it now trashed? if not, I would wait on a tranny swap and get the gears addressed before fixing something that isn't broke, especially before going to 35's

 

Yes my tranny I have in it now won't shift into third. First and second are all I have.

 

You really need to establish a starting point.

Either a choice of transmission.........so you can then pick an axle ratio that suits the motor, tires & top gear of the chosen trans......

......or, determine your existing axle ratio so you can make the best transmission choice, given your driving speed & new tire size (which might force you to change gearing anyway).

In my opinion, without modification an AOD will have a limited life in your truck, especially with 35's; a C6 won't have those durability problems, but it won't give you the economy of overdrive & a locking torque converter.
With 35" tires, lacking OD is probably not such an issue, but that's one reason you need to know your gearing.

A consideration with any 3-speed transmission (vs 4-speed), is that if your axle is geared for high speeds on the highway, low speed performance will be more sluggish; alternatively if you gear for lower mph performance, engine rpm will be higher on the highway; a 4-speed trans can compensate for this more.

Here's a calculator that Dave (Franklin2) was referring to - https://www.ford-trucks.com/calculators/mph-rpm/