Convert manual to auto

[User811780]

I have an ‘81 f150 2wd long bed with 300 and a T18 transmission that I’m looking to convert to automatic. (I know, just sell it and buy an auto, due to sentimental reasons I’d rather go through with the conversion)

There is a local ‘81 f150 2wd long bed auto with a 5.0 302 that is for sale near me. Would the transmission be “swappable” on these?

[85pig]

300 and 302 share bellhousing bolt patterns, so an auto from behind a 302 will work behind the 300. Make sure you get the block plate, as the standard and auto are (I'm 99% sure) slightly different. Grab the auto steering column, too.

You've got the mechanical clutch linkage too. I'd like to have a set of that hanging around.

[ArdWrknTrk]

Perhaps you didn't get the email I sent when I confirmed your membership.

I'm going to ask that you make an introductory post in the New Members Start Here section so we can know a bit about you and that you've seen the members guidelines.

With a C5/6 transmission you're going to need a source of vacuum for the modulator and if the transmission is AOD you definitely need an aftermarket (likely Lokar) kickdown cable, since the 300's carb is set way off on the right a kickdown linkage from the donor won't fit.

And though the C-series transmissions can work with only vacuum and without the rod, an AOD will eat itself without a TV rod or cable.

Look for the T code on the door sticker or -P R N OD D 1- on the selector.

You might also want the carpet without a hole on the hump but I have no idea what the interior of the donor looks like.

[FuzzFace2]

300 and 302 share bellhousing bolt patterns, so an auto from behind a 302 will work behind the 300. Make sure you get the block plate, as the standard and auto are (I'm 99% sure) slightly different. Grab the auto steering column, too.

You've got the mechanical clutch linkage too. I'd like to have a set of that hanging around.

Note the flex plate from the 302 WILL NOT work as the balance is different between the 2 motors.

You could swap parts between the 2 trucks, just need the right flywheel for the 302 and a motor side linkage pivot as the 300 six one will not work with the 302 also.

Then you could sell the donor truck.

BTW if you want to sell the 300 motor side pivot I would like to buy it.

I would like a spare for when mine breaks again

Dave ----

[mat in tn]

300 and 302 share bellhousing bolt patterns, so an auto from behind a 302 will work behind the 300. Make sure you get the block plate, as the standard and auto are (I'm 99% sure) slightly different. Grab the auto steering column, too.

You've got the mechanical clutch linkage too. I'd like to have a set of that hanging around.

there are a couple more details than that but yes, it is a perfect swap to do. everything should be able to be found. especially if you were to get a donor truck as a whole. there are fine details and idiosyncrasies though. the flex plate (flywheel for an auto) is a key piece as it must be made for the engine and type of trans. not all autos are the same. the length of the trans as a whole is often a different length so a different drive shaft will need to be used. autos need a linkage between the carb/throttle body to modulate internal fluid pressure and a manual will not have this linkage. there is a little wiring involved as you change over clutch lockout for neutral safety switch and backup light switch. Swapping the dash brace/ pedal assembly is a bit involved but I have seen it done without changing it (I guess it depends on the ocd of the person doing it) there is the steering column which is also the auto shifter and don't forget the brackets and linkage for that. there is bit more too but I'm sure I will think of them. maybe I will get reminded.

[85pig]

300 and 302 share bellhousing bolt patterns, so an auto from behind a 302 will work behind the 300. Make sure you get the block plate, as the standard and auto are (I'm 99% sure) slightly different. Grab the auto steering column, too.

You've got the mechanical clutch linkage too. I'd like to have a set of that hanging around.

Note the flex plate from the 302 WILL NOT work as the balance is different between the 2 motors.

You could swap parts between the 2 trucks, just need the right flywheel for the 302 and a motor side linkage pivot as the 300 six one will not work with the 302 also.

Then you could sell the donor truck.

BTW if you want to sell the 300 motor side pivot I would like to buy it.

I would like a spare for when mine breaks again

Dave ----

Good catch on the flywheel/flex plate; forgot about the balance difference.

[FuzzFace2]

there are a couple more details than that but yes, it is a perfect swap to do. everything should be able to be found. especially if you were to get a donor truck as a whole. there are fine details and idiosyncrasies though. the flex plate (flywheel for an auto) is a key piece as it must be made for the engine and type of trans. not all autos are the same. the length of the trans as a whole is often a different length so a different drive shaft will need to be used. autos need a linkage between the carb/throttle body to modulate internal fluid pressure and a manual will not have this linkage. there is a little wiring involved as you change over clutch lockout for neutral safety switch and backup light switch. Swapping the dash brace/ pedal assembly is a bit involved but I have seen it done without changing it (I guess it depends on the ocd of the person doing it) there is the steering column which is also the auto shifter and don't forget the brackets and linkage for that. there is bit more too but I'm sure I will think of them. maybe I will get reminded.

Mat also good catch on the carb linkage thing is he wants to put the auto from a 302 into a 300 truck and it uses a different linkage set up that could be hard to come by but ..........

I wounder if he could find a cable from Lokar that would work?

The auto NSS is another thing needed to work out, back up light connection should not be hard.

Dave ----

[ArdWrknTrk]

there are a couple more details than that but yes, it is a perfect swap to do. everything should be able to be found. especially if you were to get a donor truck as a whole. there are fine details and idiosyncrasies though. the flex plate (flywheel for an auto) is a key piece as it must be made for the engine and type of trans. not all autos are the same. the length of the trans as a whole is often a different length so a different drive shaft will need to be used. autos need a linkage between the carb/throttle body to modulate internal fluid pressure and a manual will not have this linkage. there is a little wiring involved as you change over clutch lockout for neutral safety switch and backup light switch. Swapping the dash brace/ pedal assembly is a bit involved but I have seen it done without changing it (I guess it depends on the ocd of the person doing it) there is the steering column which is also the auto shifter and don't forget the brackets and linkage for that. there is bit more too but I'm sure I will think of them. maybe I will get reminded.

Mat also good catch on the carb linkage thing is he wants to put the auto from a 302 into a 300 truck and it uses a different linkage set up that could be hard to come by but ..........

I wounder if he could find a cable from Lokar that would work?

The auto NSS is another thing needed to work out, back up light connection should not be hard.

Dave ----

I didn't think the '80-'81 trucks had starter interlock.

At least the '81 EVTM doesn't seem to show it.

Edit:

I'd be sure to check the transmission cross member.

I know these early trucks can have some pretty weird mounts and automatics are usually longer than manuals.

That can be challenging to remove with the upper rail bolts trapped under the bed.

[mat in tn]

I didn't think the '80-'81 trucks had starter interlock.

At least the '81 EVTM doesn't seem to show it.

Edit:

I'd be sure to check the transmission cross member.

I know these early trucks can have some pretty weird mounts and automatics are usually longer than manuals.

That can be challenging to remove with the upper rail bolts trapped under the bed.

not certain about the ones that do or dont have the interlock but covering the bases. on the cross member, it sometimes can be turned around 180 degrees and change the offset and sometimes moved to a different set of bolt holes.

[Whisler]

I didn't think the '80-'81 trucks had starter interlock.

At least the '81 EVTM doesn't seem to show it.

Edit:

I'd be sure to check the transmission cross member.

I know these early trucks can have some pretty weird mounts and automatics are usually longer than manuals.

That can be challenging to remove with the upper rail bolts trapped under the bed.

I did that swap on an 89 F250, but my engine and trans came over together. Rather than swap columns, I used a Hurst Pro-Matic 2 floor shifter. Didn't even hook up the kick-down rod due to using Edelbrock carburetor. If I need to down-shift I just slap the ratchet shifter down a gear and back up when the need is past.