I am thinking about putting an auto into the wifes '77 Ford Bronco, currently its a 3 on the tree and don't wanna spend all the money to put it on the floor if i'm changin it out later. I'd given a friend a C6 yrs ago nvr thinking i might want to put it into this bronco. It came out of an '80 something 3/4ton van my dad had it the van had a 302 in it. If i can't get it back off him (do to i dont know if he still has it) would it work. If not what yrs should i look for in either a C6 or C4 and which would be the better of the 2 to get? I know C6 is supposed to be better just not sure about parts and expense.

 

The c6 (good tranny) will work but not for free! It's going to need an adapter to go to the d20. You'll have to get your drivshafts changed due to the longer lenght. Plus you will need to move the cross member.
If your not putting a 500 hp monster motor in a c4 is easier. They can usually be had on ebay or Bronco forums for $200-300 needing a rebuild. Get a early bronco specific one with the adapter if at all possible.

 

Since it is set up as a standard. Would it be that hard to just swap in a 4spd? If so what is a good 4spd to look for and would it be an almost direct bolt in? Trying to find the easiest but best way to get away from the 3spd....

 

So 4 and 5 speeds aren't too hard to do. Here's a link to a classic bronco tech folder. On the bottom right hand side is a tranny guide. It has some very good reading in it.
http://classicbroncos.com/tech.shtml

 

The NP435 light truck 4 speed is the easiest and cheapest to do. And they are very common so finding one is easy. You are looking for a 65-80's 2wd (the late 60's early 70's 1/2 ton 4wd's with the single speed Dana 21 transfer case will work as well) with a compound low first gear. It will have a cast iron case with an aluminum top cover and a tall shifter coming out of the cover.
You would need to cut a hole in the center of the floor for the shifter and tower to fit. The adaptors are available from most of the Bronco shops and you can find them on Ebay pretty cheap from time to time. The economy versions are made from OE Bronco adaptors which have been cut down and had a machined plate welded on. There is nothing wrong with doing this. But be aware that if they aren't centered or welded together straight and true, it can cause major headaches. Shouldn't have any problems if you get them from the reputable suppliers.

There is also the option of the Mustang car 4 speed. It is built really similar to the Bronco 3 speed (can use the same adaptor, with slight mods). These transmissions are getting hard to come by and pretty expensive. They are a fun transmission for a mostly street driven Bronco. But they are really high geared for the dirt.

Jason

 

The Borg-Warner T18 or 19 is an option also. Not much difference over the NP 435. Top loader style 4 speeds are not hard. They are one inch longer, but you use most of the original Bronco parts. An output shaft from Advance Adapters is needed for any of these for conversion. There is also the top loader 4 speed overdrive available. Its cast iron and just like the older model. In the mid 80's a top internal shifting top loader 4 speed overdrive came in 1/2 and 3/4 ton pu's. Not strong as the NP 435, but work well for normal usage. Little to no mods needed for shifter assembly to clear dash. And usually doesnt get in the way of any A/c units like the granny models.

 

Well i think we've decided on just having the 3 put to the floor. Then we'll start a piggy bank to get a C-4 (if i'm lucky i'd like to just score a complete C-4 already mated to a D-20 so i can do a swap knowing they are already mated) yes i know i'll prolly be wasten money. But the wife is really wanting to drive her bronco and atm the linkages on the column bind up usually locking you in 2nd and usually it's when you are at a stop light.