I recently picked up a 1955 F100 with a ‘69 351W and an AOD transmission. I’ve lost both drive and overdrive so I’m wondering if I should have this AOD transmission rebuilt, put in a new transmission, or take the opportunity to convert to a manual transmission? If your recommendation is a new transmission or converting to a manual what transmission do you recommend?

 

I really like shifting gears.
To me, it is fun.
Having said that, driving through town gets old when you have to shift all the time. The older I get, the less I like it. When I was growing up, if you wanted the most heavy duty transmission, you bought a manual. Today, the highest rated pickups have automatic transmissions.

When building my 55, I was thinking about a Tremec 5 speed or 6 speed. After thinking about it, I decided to go with a late model automatic.

For your particular situation, rebuilding what you have is not a bad idea, if you have someone qualified to do it at a reasonable price. Late model automatics are good, but the electronics adds a lot of issues.

There are many experts on this site that will have good info for you. I would definitely stick with an overdrive transmission.

 

For me, the question becomes, why did you buy a vehicle that's almost 70 years old? You probably didn't do it because you needed it to get yourself to work or the grocery store or to church. You probably have one or more comfortable reliable daily drivers around for those kinds of chores--so why did you get the 55 F100? Did your dad have one or your grandfather? Maybe you think you might enjoy socializing at week-end car shows?

It just puzzles me that people with old vehicles oftentimes pour in extraordinary amounts of time and energy and money to make something from the distant past drive and perform like the modern vehicles they already have. My advice is look for an original stock engine and transmission--and don't try and force your new project truck into something it's not. An engine with a 351cubic inch displacement seems like way too much power and speed for stock steering, brakes, and suspension.

My truck has a 101 hp engine and a 4 speed non-synchronized manual transmission. It squeaks and rattles and only has one wiper and no radio. It's not very fast or comfortable, and double clutching takes some getting used to--but driving it is an altogether different experience from what I've grown accustom to--and I like that. It looks and drives and sounds like trucks did 70 years ago--and that's why I have it. Now you have to decide why you have yours.

Good luck and welcome. You'll get lots of advice from all different perspectives here.

Jim

 

Jim,you have said that very well and exactly my thoughts, I have copied your reply for future reference

 

For those who were blessed with a nice truck that still had original running gear, I can see rebuilding one to original condition.

I really respect those who have the talent and tenacity to do an original restoration.

For those of us who bought trucks that have already been modified, your choices are limited. The limits are usually accessibility to parts, and money. Trying to find decent, original parts that are about 70 years old is not easy.

The OP has bought a truck that has already been modified. My bet is that most old trucks out there have been modified in the last 70 years. Since money is an issue for most of us, the least expensive, and reasonable option for the OP is probably to rebuild what he already has.

For me, my truck had a FE engine with a manual transmission. Neither one was in working order.
Finding an original running gear, and totally rebuilding them would probably cost more than my Coyote engine and 10R80 transmission.

Hopefully there are folks that have some experience with the 351 and AOD combo, to help the OP.

 

Most definitely your quickest, easiest and least expensive way out is to rebuild your existing transmission. I've seen a lot of people give the AOD a bad rap over the years, and yes, a lot of improvements were made to it over the years, the later ones are better than the early ones, but for a knowledgeable builder, it can be a really good trans. Shop around and find a shop or builder you're comfortable will do a good job and you'll be happy, getting back on the road quickly. My 2c.

 

I don't disagree about the need to consider costs when making decisions about how best to get your project truck back on the road. As noted, the OP, truck already has a 351 engine out of a 69 truck. This engine, however, may or may not be practical or reliable. It is after all 50 years old. It very well may need a complete rebuild--in which case searching for a stock drive train may not be such a cost prohibitive approach.

Then the question must be asked if there are any of our members running big engines like the OP has that haven't felt the need to up-grade their brakes? After brakes comes wheels and tires, then steering, a modern suspension, maybe brighter headlights...It goes on and on, and pretty soon you don't really have an old truck anymore with any sort of connection to the past. You have instead a vehicle that drives and performs almost as well as your daily drivers, at what? Maybe four times the cost?

...just my take on things. Everyone has their own reasons for doing what they do with their trucks. It's all good.

Jim

 

I would put only a fraction of the miles on my coupe if it were stock . Not everyone enjoys the visceral experience of operating a vintage truck but may love the looks . I think the biggest question is what is he going to use it for ? To me that decision has been made or he would have purchased a stock one . As far as the engine needing rebuilding I believe that would apply to a factory one also . For the brakes and steering being up to the task we have no idea what it has .The easiest option would be to rebuild it as mentioned

 

To Jim, he never said the engine came from a truck and 351w were used by Ford into '96, but none of that matters because that is not what he came asking about.
That being said, to the OP, it all depends on what you want your driving experience to be. Me, I like manuals for my toys and autos on my work/daily drivers. Like already stated the cheapest route is to rebuild what you got, but then that is not what you asked. What you asked is a question that can only be answered by you. Your truck, your money and your time, you decide. Did I tell you I like manuals.😊

 

If your AOD lost only drive and overdrive, the diagnosis is one of only three things. The direct clutch is smoked, the direct drive shaft is broken or the direct drive hub in the torque converter is broken. If its the direct drive shaft, it can be accessed without disassembling the transmission. It literally pulls right out of the front of the input shaft after the transmission is out.

 

Thanks for that info. I’ll see if I can find someone that knows the AOD’s.

 

I know from posts in the 80> on the AOD that they use a throttle cable to adjust the fluid PSI and if this is not adjusted right can burn up the trans in no time.
It seams also it is hard to get this adjustment right when running Holley carbs even with their adapter as it just dose not get the ratio right.
I would find a shop that knows the AOD and have them rebuild it with better parts if it dose not have them in it now.

Also note there is a EOD that uses a computer and not the cable to adjust the PSI but I hear this computer is some $$$
Good luck with your project
Dave ----

 

When one buys a vehicle with modern engine and drive components how does he know the quality of the work that was done to accommodate that change. Seems like there may be some structural changes that were done so that you now can go 70+ MPH in a 70+year old vehicle.

 

If I remember correctly there is a valve body available that eliminates the need for the td cable , that being said there is nothing wrong with a properly set up aod . Do you know if this combo was used in this truck and if so the amount of time-miles ? It may help to determine the reason for failure or a least eliminate some .

 

I agree Ed, but I'm thinking a vehicle with a 351 engine can go much faster than 70 mph. In fact, it can probably go every bit as fast as a modern daily driver with multiple air bags and numerous other safety features engineered into its design. Just because a 70 year old truck happens to come with a powerful engine (not compatible with the original vehicle's design) doesn't necessarily mean it couldn't be replaced. My point to the OP is that going back to a stock drivetrain might very well be less expensive in the long run than re-engineering his truck to safely accommodate the power and speed the over-sized transplanted 351 engine it came to him with makes possible.

The OP apparently is going to look into repairing his AOD transmission which is fine, but as Ed reminds us, there may be other expenses and upgrades that need to be considered.

Jim