4-Speed Manual to C6 Automatic Transmission Swap
 

The two trucks:

1985 Ford F150 XL 4.9L T18/T19 Regular Cab LWB 2WD
1984 Ford F150 XL 5.0L C6 Regular Cab SWB 4WD

I'm wanting to take the 4-speed manual out of my 1985 F150 and replace it with the C6 that I have in my 1984 F150. I know that the 1984 is four-wheel drive, but I plan on bringing the transfer case with the transmission, as I plan on swapping the 4x4 front differential in the near future.

The reason for this swap (as bad as I hate it) is because I've totally given up on my wife learning to drive it. Plus, we're about to buy a 24' pontoon boat, and I don't want this thing to come backwards on any of these steep (and I mean STEEP) boat ramps that we have around here.

So, with that said, the only thing that I see working out is just swapping the C6 out of the 1984 into the 1985.

The 1984 has a 302, so the bellhousing will work. But, will the flexplate from the 302 work with the 300?

The 1984 is a donor truck, so I will be able to pull the column, shifters, linkages, etc. from it to convert the 1985.

As the two trucks are the same, except for one being long-wheel base and the other short-wheel base, the transmission/transfer case mount will bolt directly into the 1985, correct?

The only thing that I should have to have fabbed up is a driveshaft as far as my figuring goes.

If there's anything that ya'll think I'm missing, please let me know!

Nightrain

The flexplate won't work. The 302 has an unbalanced plate while the 300 is a balanced plate. You have everything else figured out, and you probably also realize you will need to swap radiators for the tranny cooler lines for the automatic.

I like the c6 automatic, and I like automatic tranny trucks myself for hitching up trailers and manuevering around tight places.

Thanks for your reply, Dave.

So, I'll need a flexplate for a 300 and some type of cooling system for the tranny.

I thought of swapping radiators from the 1984, but I'm thinking of finding a 4-row for the 300 and then an aftermarker fluid cooler for the transmission.

I've always liked a 4-speed, especially with a 300-- ain't hard to get that baby talkin' and chatterin' like a big CAT. But, as I said earlier, I don't want this thing going back in the water when I'm trying to pull that pontoon up the ramp. I know that the 300 is a tow-horse, but I just don't trust that 'ol clutch and the wifey's going to have to drive the truck every now and then.

Thanks again for your reply. ;)

Nightrain

:) Uhhhhhhhhhhh,the 300 is ZERO balance on flexplate.302 is either 28 or IIRC 52 oz on flexplate.Depending on year.
Leo

28oz or 52 oz of weight on the flexplate or flywheel would make it unbalanced wouldn't it?

:) In case you have`nt figured it out.They DON`T put that much weight on the flexplate.
Leo

How much weight do they put on a 28oz flywheel(or flexplate)?

302's of the 'Windsor' variety are externally balanced engines and require flexplates/flywheels AND harmonic balancers which are balanced with an offset weight. They won't balance on their own, but a combination of flywheel/crank/balancer is dynamically balanced.

Up until the roller motors, the 289's/302's had a 28oz weight on the flywheel outer edge. From the roller motors onwards (and also identifiable by the 4 bolt pulley mount on the front harmonic balancer) they used a 52oz weight on the flywheel.

Bottom line, get the flywheel/flexplate designed for the motor.

I would save the trouble of the column and just use a floor shifter. If you do be sure you put the Tcase shifter in first, so you won't run into fitment issues. The cross members are different from 2wd to 4wd, but you should have one in the donor, and they bolt in the same. You will have to have a driveshaft made, Probably just have the front yoke from the 4x4 shaft welded on the 2wd shaft at the proper length, and have it balanced....It will need shortened quite a bit unless your truck has a carrier, which it shouldnt(but might). As for tranny cooling. You can check your current radiator it probably has fittings for the auto, they probably are just plugged off instead of having lines in them. If not, just pull the radiator from the other truck, and spare the lines. Make sure you remember to reconnect the vacuum on the tranny otherwise you'll be in for a ride that first trip lol

i don't know how much trucks are around there but if all you need is to pull a boat, I would consider just buying another truck. Thats a lot of work to go from a manual to an auto and a lot of down time too. I see fords a lot on CL for 300-1000 in the denver area...

just my 2c

what if he likes the truck he's got?

I look at cost-effectiveness.

I bought the 1984 4x4 for $500 with no title. This guy I work with had a horrible experience with eBay (as alot of folks do), and the seller never came through with the title.

So, I give him $500 for it. It runs, the body is fair, the transmission, transfer case, and the differentials are in good working order.

With that said, $400 for my 1984 F150 and a tranmission from a truck that I only give $500 for puts me at $900 in the 'ol rig. If I ever wanted to sell it (which with an automatic means anyone with a drivers license could drive it), I'd have a bigger chance of getting more money.

So, I don't see any sense in going out and buying another truck. Pointless to me when I've got everything I need right here, and don't mind doing the swap.

Nightrain

I stopped and talked with a good friend of mine that rebuilds transmissions the other day and threw my idea out to him. And, he gave me a new one...

He asked why didn't I just go ahead and use a beefed-up AOD? I told him because I've already got the C6 at home in the other truck. But, he said that he would take the C6 4x4 trans as a core for an AOD 4x4. For his price, (I think he gets $1250 for a reman. AOD), and my C6, he'll even toss in his 3-year warranty and throw me in a shift-kit at cost.

But, my question to ya'll is... Will the overdrive that the AOD offers save me enough fuel mileage to pay for itself? Right now, this 300/T-18 combo is getting about 18mpg. I know that the C6 is going to kill that, but will an AOD put me under 15mpg?

Thanks for any suggestions fellas!

Nightrain

keep the c6. i don't like AODs a bit.....and pulling a boat you probably won't use OD anyhow. It won't save you as much fuel as you think. Buy a book ($20) and rebuild the c6 your self. I got a haynes manual a couple years ago and did my first one having never seen the inside of a tranny, it's stilling going in my mud truck. C6's are easy to rebuild and don't require any overly special tools.

Thanks for your reply!

I thought of going to the AOD, but with no more interstate driving than what I do, I don't see that it would be cost-effective.

Just how hard is it to rebuild a C6? Any special tools required?

Nightrain