I’m restoring my truck. I want to convert from manual to automatic. Is this feasible or sensible? What do I need to know? What will work? What won’t work?

1979 Ford F250 4x4, regular cab, long bed, 4.9L 300, NP435 transmission, and NP205 transfer case.

I’m thinking of swapping to a C6 automatic transmission and swapping the steering column to the stock column with the automatic shift lever and PRNDL indicator.

- Did Ford offer this truck in this configuration?
- I assume there are some shift linkages associated, is that correct?
- Is the pedal assembly different or can I simply remove the clutch pedal from the old pedal assembly?
- Will the C6 trans be able to connect to transfer case?
- Will the C6 transmission work with the NP205 transfer case?
- Will I need a different adapter between the C6 transmission and NP205 transfer case?
- Will I need a different crossmember or transmission support?
- Will I need to change the length of either of drive shafts?
- Is the wiring harness different?
- Will the Speedo cable connect to the C6 transmission?
- I plan to change the center floor cover to the lower profile cover for the automatic.

I really appreciate any advice and help I can get. I know there will be some people that say to keep the manual transmission, but I have my reasons including a paralyzed family member that can’t drive an standard/manual transmission vehicle. Thank you.

 

How about we swap trucks, I have a 79 same truck with the 351M, lot more C6's out there for them... and I want another one with the 300

Seriously, it can be done, I personally have never done it, me, I would look for an auto, unless the truck has sentimental value.

 

Easy swap. If you're keeping the 300, you might consider going to an AOD to get the benefit of an overdrive. Whatever tranny you're getting just make sure you get the one with the right bellhousing (sbf for your application) and you will be good.

 

It is indeed sentimental. It was a family ranch truck that was put through a lot of hard work. Now it’ll be a city truck that only gets into the dirt for exploring and camping. No more hauling hay or wrangling cows for this truck.

 

C6 to NP205 will work fine, lots of those out there...
It's been a few years since I did my swap.
My swap was pulling the NP435 manual transmission from a 75 crew cab short bed I own and replacing it with a C6 auto from a 73 regular cab long bed I owned.

This was on 360 FE motors so I know it's not the same as your 300, but hopefully it is helpful, though I'm not sure if a 1979 F-250 300 cyl inline 6, 4x4, auto was made.

I made my crew cab into an auto and the 73 highboy into a manual.
It's not possible most of the time, but honestly having two running and driving trucks to swap parts between is the easiest way to do this conversion as all the parts you need are there. Collecting parts bit by bit is time consuming and puts the swap on hold when you run into needing something no one else mentioned so you were unaware of it.

The first thing I did was remove the steering columns out of both trucks and switch them.
I also swapped the pedal assemblies and shifter linkages.
I had to buy a new auto speedo cable due to frame length differences between my trucks.
Make sure you get the flexplate/bolts, transmission cooler lines, inline trans cooler, trans hump cover, NSS wiring, shifter boot rubber, chrome ring, etc
May even want to consider swapping radiators if yours doesn't have provisions for the trans coolers.
Check into flywheel teeth and starter engagement length.

In the crew, I lengthened the holes in the rear automatic transmission cross member (made them oblong instead of round) until I was able to get the bolts to line up in the holes. Nothing extreme and I have an extra crossmember in case I decide to do it differently in the future. From taking a look at the crossmember just now in my crewcab I couldn't even tell that I'd made any type of modification.

I know this doesn't fully answer your questions but I hope it helps.

 

Thinking about this more, I realize I did this swap on divorced transfer case highboys and you have a married transfer case truck so my confidence in this being possible for you just decreased because I've only dealt with this on divorced transfer case trucks.

You'll also need to check into brake pedal rod similarities and/or differences. (curved/fulcrum vs straight)

I found this thread on 400 swaps... where again one of the recommendations was to have a complete donor truck, https://www.ford-trucks.com/forums/1...nual-swap.html so I guess if you find a 1979 F-250 300 cyl inline 6, 4x4, auto you'll know this is possible.

 

Here is a great thread on the opposite conversion, so maybe you can use that info and reverse technology it?
https://www.ford-trucks.com/forums/9...planation.html