Swap to an Automatic
- Thread starter bud2005
- Start date
Scoutboy74
Moderator
Welcome bud. Yes, it is doable. Hopefully the trans from your donor '72 is a tf 727 rather than a borg warner. You should confirm this as some of the associated parts will depend on which one you have.
Scoutboy74
Moderator
I agree that a '71 with auto is almost certainly going to have a bw. The way to make positive id is by looking at the trans unit itself. A bw is a two-piece cast iron case. The bell portion can be separated from the main case. The tf 727 is a one-piece cast aluminum case. The bw's are good units, however overhaul/repair parts are harder to source than 727 stuff is. Is this trans in a good state of repair?
I didn't catch this in your initial post, but you mentioned that your builder is a '74 1210. Something isn't right there. A '74 3/4 ton would be a 200. The 1210 designation ended with the '73 model year. This could be an important distinction to be accurate about as the engines were set back in the frame for the '74-75 model years. If your engine in the builder truck has rear Dump exhaust manifolds, that means it is the setback design and would indeed be a '74 200.
see edit.
I didn't catch this in your initial post, but you mentioned that your builder is a '74 1210. Something isn't right there. A '74 3/4 ton would be a 200. The 1210 designation ended with the '73 model year. This could be an important distinction to be accurate about as the engines were set back in the frame for the '74-75 model years. If your engine in the builder truck has rear Dump exhaust manifolds, that means it is the setback design and would indeed be a '74 200.
see edit.
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Scoutboy74
Moderator
Okay. Good to have the particulars out of the way. You might not think so at first blush, but these things can have a huge bearing on the how's, why's and wherefores. Lemme grab a hop pop, and I'll get to work on your laundry list for this swap. Stay tuned.
Scoutboy74
Moderator
This will be more of a "what you need" rather than a "how to remove it" primer. I'm going to try to be as thorough as possible, but I reserve the right to leave out something critical. This advice will only be worth what you had to pay to get it and not a penny more.
You'll need to harvest the following parts from the '71 donor:
1. Support the rear of the engine and remove the bw transmission, torque converter and any associated accessories such as fluid cooling lines, shifter linkage, vacuum modulator, heat exchanger etc. Take reference pics of how these items are assembled before the first wrench turn. You'll most likely need to remove the trans x-member in order to clear the tranny. Once that's out, compare it carefully to the x-member in your '73. They might be the same, but if they're different, you'll need to swap it over too.
2. Remove the flexplate (ring gear) complete with case-hardened bolts and crank hub spacer.
3. Remove the complete steering column assembly. You need the column shift capability with the integrated neutral start switch, plus the actuator where the shift linkage attaches on the engine side of the firewall.
4. Remove the brake pedal assembly. This is optional. If you want the wide pedal pad associated with the auto trans, then you need to harvest it. Otherwise, you can just remove the clutch pedal from the '73 and survive with the narrow ass brake pedal.
5. Remove the floor mounted kickdown switch under the gas pedal. The borg warner drive to 2nd and 2nd to 1st downshifts are actuated via this electrical switch. You'll obviously need to fashion the same hole in the floor of your '73 to accommodate this doo-Dad.
6. Remove the trans tunnel cover. The one in your '73 is going to have a gaping hole where the floor shifter once was, but the cover form the '71 4x2 doesn't have a hole for the 4x4 shift lever. So, you can either fabricate a cover for the shifter hole on the '73 cover, or you can cut a hole in the '71 cover for the t-case lever. Your option. Personally, I'd rather measure twice and cut one new hole in the blank, than attempt some half-azz patch job, but you might be better with sheet metal than me.
7. Pull the radiator (optional). If it is in good condition and plumbed with the fittings for an internal fluid cooler, you May opt to swap it over. If not, you will need to source an external fluid cooler of adequate capacity. The ultimate option is to use an external cooler in conjunction with an internal one, especially if you plan on towing or hauling heavy cargo.
Now on to the '73:
1. Support the rear of the engine and remove the manual trans.
2. Remove the clutch pedal assembly, and narrow brake pedal also if swapping to the wide pedal.
3. Remove the flywheel, plus case-hardened bolts and crank hub spacer. Avoid mixing these items up with the corresponding donor parts. Now would be a good time to replace the rear main seal and rear freeze plugs.
4. Install the hub spacer, flexplate, and case bolts with thread sealer applied, to the rear of the engine and torque to spec.
5. Remove the steering column assy and replace with the donor assy.
6. Install the kickdown switch under the gas pedal.
7. If the torque converter was removed from the auto trans, ensure that it is re-installed all the way in so that the slots on the converter shaft are fully engaged with the drive tangs on the oil pump rotor. Improper alignment will result in damage to the pump rotor and unit failure.
8. Install the bw into the '73, supported by the appropriate x-member.
9. Connect the shifter linkage, vacuum lines fluid cooling lines etc etc in the same manner as they were on the '71, referring to your pics as needed.
Now comes the * and the ** portion of the show.
* is in regards to your steering column wiring. Because you're now dealing with a column-shifted auto, you are likely to encounter some differences in the associated circuitry housed within. You May have to improvise a little.
** deals with possible coupling issue(s) from the output of the bw to the input of your divorced t-case. There May be a difference in overall length of the units for one thing, and shaft to yolk agreement issues for another. Having never performed this exact swap myself, I cannot say for sure what you May be up against here. All I can do is make you aware of the possibility. Once again, this could well be an opportunity for improvisation, albeit in a safe and responsible manner. I hope this helps. Good luck on your exciting journey.
You'll need to harvest the following parts from the '71 donor:
1. Support the rear of the engine and remove the bw transmission, torque converter and any associated accessories such as fluid cooling lines, shifter linkage, vacuum modulator, heat exchanger etc. Take reference pics of how these items are assembled before the first wrench turn. You'll most likely need to remove the trans x-member in order to clear the tranny. Once that's out, compare it carefully to the x-member in your '73. They might be the same, but if they're different, you'll need to swap it over too.
2. Remove the flexplate (ring gear) complete with case-hardened bolts and crank hub spacer.
3. Remove the complete steering column assembly. You need the column shift capability with the integrated neutral start switch, plus the actuator where the shift linkage attaches on the engine side of the firewall.
4. Remove the brake pedal assembly. This is optional. If you want the wide pedal pad associated with the auto trans, then you need to harvest it. Otherwise, you can just remove the clutch pedal from the '73 and survive with the narrow ass brake pedal.
5. Remove the floor mounted kickdown switch under the gas pedal. The borg warner drive to 2nd and 2nd to 1st downshifts are actuated via this electrical switch. You'll obviously need to fashion the same hole in the floor of your '73 to accommodate this doo-Dad.
6. Remove the trans tunnel cover. The one in your '73 is going to have a gaping hole where the floor shifter once was, but the cover form the '71 4x2 doesn't have a hole for the 4x4 shift lever. So, you can either fabricate a cover for the shifter hole on the '73 cover, or you can cut a hole in the '71 cover for the t-case lever. Your option. Personally, I'd rather measure twice and cut one new hole in the blank, than attempt some half-azz patch job, but you might be better with sheet metal than me.
7. Pull the radiator (optional). If it is in good condition and plumbed with the fittings for an internal fluid cooler, you May opt to swap it over. If not, you will need to source an external fluid cooler of adequate capacity. The ultimate option is to use an external cooler in conjunction with an internal one, especially if you plan on towing or hauling heavy cargo.
Now on to the '73:
1. Support the rear of the engine and remove the manual trans.
2. Remove the clutch pedal assembly, and narrow brake pedal also if swapping to the wide pedal.
3. Remove the flywheel, plus case-hardened bolts and crank hub spacer. Avoid mixing these items up with the corresponding donor parts. Now would be a good time to replace the rear main seal and rear freeze plugs.
4. Install the hub spacer, flexplate, and case bolts with thread sealer applied, to the rear of the engine and torque to spec.
5. Remove the steering column assy and replace with the donor assy.
6. Install the kickdown switch under the gas pedal.
7. If the torque converter was removed from the auto trans, ensure that it is re-installed all the way in so that the slots on the converter shaft are fully engaged with the drive tangs on the oil pump rotor. Improper alignment will result in damage to the pump rotor and unit failure.
8. Install the bw into the '73, supported by the appropriate x-member.
9. Connect the shifter linkage, vacuum lines fluid cooling lines etc etc in the same manner as they were on the '71, referring to your pics as needed.
Now comes the * and the ** portion of the show.
* is in regards to your steering column wiring. Because you're now dealing with a column-shifted auto, you are likely to encounter some differences in the associated circuitry housed within. You May have to improvise a little.
** deals with possible coupling issue(s) from the output of the bw to the input of your divorced t-case. There May be a difference in overall length of the units for one thing, and shaft to yolk agreement issues for another. Having never performed this exact swap myself, I cannot say for sure what you May be up against here. All I can do is make you aware of the possibility. Once again, this could well be an opportunity for improvisation, albeit in a safe and responsible manner. I hope this helps. Good luck on your exciting journey.
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Scoutboy74
Moderator
You bet. Obviously there is a lot involved in this swap. You must have some pretty strong motivation for wanting to do so. I can see the distinct possibility of someone scanning through this thread and wondering why go through all the trouble? If you are so vehemently opposed to the standard trans, why not just make the '71 with auto the driver and use the '73 as a parts truck or sell it off? Of course they are yours to do with as you see fit. I'm just curious. If you'd care to shed any light, that would be great. If not, that's okay too.
Scoutboy74
Moderator
Understandable about the title and 4x4 situation. Ahh, the exuberance of youth. I'm still curious about one thing though. Do you have something against manual transmissions, or are you just that enamored with automatics...or both? In my case, both of my binders have auto's in them and that's just how things worked out. There are times that I'm glad I have the slushbox in my Scout, like when I'm making a slow climb up steep, rough terrain. Its nice not to have work a clutch in that scenario, just feather the skinny pedal. Most of the time though, I think I'd prefer to have a manual trans. Too each his or her own.
Scooter
Active member
As a side note.
Instead of a column shifter, there's always the floor mounted shifter. Both my 73 and 74 have the 727 auto and have the floor mounted shifter.
The trans cover can be sourced out and swaped for one that is for the auto. The bw trans May be different configuration than the 727 shifter is. But if it's cable operated it does have some flexabilities.
Getting the registration on the 71 can be done. Just a big hassle. That involves said vehicle getting inspected and weighed, along with new id tags. Or going through dmv saying the pink has been lost over the years. There's more to it I'm sure, but those are the basics.
I did the same type of swap in my 72 - from manual to automatic. I went the extra step to remove the clutch/brake pedal assembly and installed the wider brake pedal. Basically maken it look stock as if it came that way from IH floor. My excuse was that the manual trans was crap and it kept popping out of first. And it got real tired having to shift constantly while dealing with stop and go traffic. That's my excuse and I'm sticken to it
Instead of a column shifter, there's always the floor mounted shifter. Both my 73 and 74 have the 727 auto and have the floor mounted shifter.
The trans cover can be sourced out and swaped for one that is for the auto. The bw trans May be different configuration than the 727 shifter is. But if it's cable operated it does have some flexabilities.
Getting the registration on the 71 can be done. Just a big hassle. That involves said vehicle getting inspected and weighed, along with new id tags. Or going through dmv saying the pink has been lost over the years. There's more to it I'm sure, but those are the basics.
I did the same type of swap in my 72 - from manual to automatic. I went the extra step to remove the clutch/brake pedal assembly and installed the wider brake pedal. Basically maken it look stock as if it came that way from IH floor. My excuse was that the manual trans was crap and it kept popping out of first. And it got real tired having to shift constantly while dealing with stop and go traffic. That's my excuse and I'm sticken to it
Scoutboy74
Moderator
The pickups and t/a's with autos do not use the floor shifter and cable. The tunnel cover is also completely different between Scout II's and pick-alls. Sure, if one had an sii floor shifter and cable on hand and wanted to badly enough, one could probably cobble it into place and make it function in a pick-all. This style of shifter in combination with the bw auto would not allow for a park/neutral start system, as that feature is integrated into the shifter of bw auto rigs. Scout 800's with the bw had the ns switch integrated in the floor shifter, but those are much harder to come by than the sii floor shifters. Hard core wheelers with auto equipped trail buggies actually prefer to have the ns disabled. It allows the starter to be engaged in any gear position, lurching the vehicle into motion as soon as the engine lights off. Bypassing this safety feature is not recommended for the masses. Just my opinion bud, which you are always free to take or leave as you please, but I think you're already opening up a big enough can of worms without having to custom fit a floor shifter on top of it all.
Scoutboy74
Moderator
You're thinkin' outside the box, man. Nothing wrong with that. I try to point out the facts that I know of when I can, and hopefully not come off as though I'm just pissing in peoples' cornflakes because I enjoy the sensation...well I do, but that's beside the point. Bud might be the kind of guy who latches on to an idea, such as floor shifting his automatic and decides, by god, that's what I want and I don't care what I gotta do to make it happen. Well, more power to him if that is the case. Done the right way, and not half-assed, it might be pretty cool and for damn sure unique. There wouldn't be any need to swap steering columns then, but it would require two holes cut into the tunnel cover to accommodate both shifters, as the hole for the manual lever is the wrong size and shape.
Scoutboy74
Moderator
I hope you're taking pictures so you can document your progress in a separate build thread later on. This is a very unusual swap project and would likely be of interest to some folks.
Scooter
Active member
Enteresting swap indeed. Now that we got the coolness facter being kicked around. Kinda how jetfxr in his hot rod build thread, has mounted his alternater on the rearend housing. And gets charging from the rotation of the rear drive shaft
as far as the gaping hole in the floor from the old manual shfiter goes, that can be easily patched up. If it's the metal version like the scouts, then a piece of sheet metal an 1/8" or so smaller than the hole can be stitch welded into place. Unless one likes watching the ground go by as they drive down the road. Maybe use it as a pissen hole.
Scoutboy:
I aint seen ya piss in anybodies cornflakes yet.
lol you'r aight, just as long you aint eaten yellow snow 
as far as the gaping hole in the floor from the old manual shfiter goes, that can be easily patched up. If it's the metal version like the scouts, then a piece of sheet metal an 1/8" or so smaller than the hole can be stitch welded into place. Unless one likes watching the ground go by as they drive down the road. Maybe use it as a pissen hole.
Scoutboy:
I aint seen ya piss in anybodies cornflakes yet.
lol you'r aight, just as long you aint eaten yellow snow