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Discussion Starter #1 (Edited)
I've seen a number of swap write-ups on the forums about this swap, but have noticed several of them have questions posted on them that I ran into during my swap. Plus, I did a few things a little differently, so I figured I'd do my own writeup.

In this case, I swapped from an AOD automatic to an S5-42 (ZF5) 5 speed manual, but it should work for a number of transmissions.

I purchased my Bronco with the full intent of pulling out the automatic and replacing it with a manual.
I originally had an NP-435 on hand, but when I was at the junk yard, I happened upon a '93 F-350 4x4 with a 351w and a manual transmission. Hence, I brought the ZF5 home with me.





At this point, I broke the transmission down to inspect it, and this first post will be about that. If you want to get right to the install, that starts with the second post.

Since I wanted to check the condition of the internals, I broke the case open. The ZF5 is rather easy to completely open up.

First, stand it on end. This is best done on two 2x4's since the input shaft extends past the end of the case.



Remove all of the bolts from the casing. Then, these pegs need to be hammered out





These caps can be a little bit of a pain, but drill a small hole and then pull them out to remove the retainer springs.



Remove the shifter handle by removing the bolts and pulling it out.



Take a pic of this so you remember how it goes back together, and then pull it out.



Next, there are two of these hex bolts that need to be removed. Mine had little plugs in them that had to be pulled out before I could get a hex head in them. These hold in the reverse idler shaft.



Once out, you can slide the whole case off.





This is the reverse idler shaft. It just slides right out. Then the reverse idler gear can be removed.





Pull the whole thing out as a single assembly.







These are the kinds of things to inspect. The "dog teeth" on the syncro gears on this transmission were pretty worn, so if I had just installed it, it would have ground pretty badly when I shifted.



This one is hard to see, but if you look close, you can see the tips of the triangles are all gone.







So, numerous syncros needed to be replaced, as well as several of the gears.
At this point, I did a cost analysis, and decided it wasn't too much more to have a shop professionally rebuild it (with warranty!), as opposed to me buying all the tools and doing it myself. But, it was good to inspect the transmission myself, see how it worked, and understand why it needed a rebuild. I brought all the pieces down to the shop, and they rebuild it and put it all back together.



A full rebuild cost about $1800, and the transmission was $150 from the junk yard, so about $1950 for a fresh ZF5.

Now that it was ready to go in, on with the swap.
 

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Discussion Starter #2
First things first was to remove the automatic.

Disconnecting the driveshafts is straight forward (if you can't to that, you shouldn't be doing a transmission swap.)
Unbolt the u-bolts and then set the driveshafts aside.



I put the u-bolts back into the yoke so I wouldn't lose them.



Next, disconnect the shifter from the transfer case and remove the 6 bolts holding it to the transmission. I'm able to slide it off and drop it down by hand, but it's about 70 - 80 pounds, so be warned.





This can be a pain depending on the amount of rust. Remove the 4 upper bolts and 2 lower bolts that hold the side brackets onto the crossmember. Then unbolt the crossmember and pull it out. On both my '81 and my '85, these were metric with the bolt head being a 15mm and the nut being an 18mm (or the other way around, can't remember exactly).



The upper bolts cannot be removed without either cutting them, or separating the body from the frame, so take really good care of them, and clean them up as best you can.



Next I disconnected the shifter linkage for the automatic lever on the steering column. This is on the driver's side on the frame.



Removed the bolts and removed the bracket, since I won't be using it again.



This is where it gets messy. I'd already drained the transmission of ATF, but these lines contain a lot more. These are the cooler lines for the remote transmission cooler. They hold a lot of fluid and can't easily be drained until you remove them.



In the case of the AOD, once the lines are disconnected, the only thing left was the TV cable. It was just a bolt attaching it, so it easily came off.
Then, the only thing holding the transmission in place are the bolts to the engine. Remove the bolts, slide the transmission back, and drop it down. I recommend a transmission jack for this.



Lots of fluid will still drain out due to the lines and the torque converter.



Slide the transmission out and set it aside. I put mine up on Craigslist and had 10 people begging for it within hours. Apparently AODs are hot commodities.



Unbolt the torque converter and take it off. It likes to spin, so an easy way to get them out is to get a long wrench and put them at an angle greater than 90° to the bolt. This puts torque on the bolt without spinning it. Once removed, the engine should be clear.



$$$



The old transmission is now out and ready for the new one.
 

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Discussion Starter #3 (Edited)
Next step is the interior. Remove the center console and both the seats, since you'll need to pull the carpet or floor mat up to get to the transmission pan.



I flopped my seats over the back bench, and it was a great spot for them.



Good time to clean the floor, too. Yuck....



Remove the door sills, and then pull the floor back.





This is only held in with screws, so remove them all and pull the whole thing off.






I wanted to go all the way, so I wanted to remove the shift indicator on the dash. On the 80 - 86, this is really easy.
For starters, remove the collar from the steering column and then remove this bolt.



This will allow the shift cable to be removed with the dash.



I won't go into the process of removal, since that's a different writeup, but remove gauge cluster from the dash.



Remove these screws from the back.



This removes the shift indicator. Now, you'll need a delete for the manual transmission. I had one on hand from another gauge cluster.







I did a poor job of taking pictures through the next part, so you'll have to forgive me. But, unbolt the bracket that holds the steering column up. Disconnect the brake pedal from the brake booster, and then unbolt the brake pedal assembly from underneath the dash. There's a large plug that goes through the middle of it that will need to be disconnected. Once it is, you can work the brake pedal bracket out. To continue, you'll need the pedal bracket assembly from an '80 - '86 manual transmission Bronco or truck.



Something to check for. Hydraulic and mechanical linkage brake pedals are slightly different. The peg for the brake booster is in a slightly different location. This will matter if you have cruise control, since it uses this for a cancel switch. If they're different, you may need to swap brake pedals.

 
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Discussion Starter #4 (Edited)
Next, and this is really important and often missed, is the firewall reinforcement plate!
This is something for ANY 1980 - 1991 Ford truck that has a hydraulic clutch.

Ford did not reinforce the firewall when they moved the clutch from mechanical to hydraulic. The extra strain and stress of the master cylinder mounted on the firewall causes it to flex, and will eventually crack the firewall. Ford fixed this issue when they did the 92+ redesign, and offered a TSB for the earlier year models. They've since discontinued the reinforcement plate, but BroncoGraveyard still sells it.

https://shop.broncograveyard.com/83-91-Ford-Bronco-Ford-Truck-Firewall-Clutch-Repair-Bracket/productinfo/34010/?gclid=Cj0KCQjw6cHoBRDdARIsADiTTzbojUdYmgKx_TWP-GHsSDoeBVWw6PKl7EsFfRsoS7EiKv-YnH9Q1OIaAqRmEALw_wcB

It's a solid, high quality piece. I highly recommend installing one. You might be okay for a while if you don't, but a few years down the road you're going to have issues. The cracks do more than just damage the firewall. The extra flexing will cause the master cylinder to move when you push the clutch, which will reduce engagement and cause gears to grind.

To install it, you'll need to remove the steering column. This is actually pretty straight forward (and is something you'll need to do anyway if you want to swap from an automatic steering column to a manual column).

To remove the steering column, unbolt the steering column from the steering box, remove these bolts from the firewall, and the steering column comes right out.



(At this point, I had the steering wheel pulled off for something else I was doing, so don't feel like you missed a step.)





The plate bolts snugly into place.



Bolt it FIRMLY in place so it doesn't wiggle around and then drill out these 5 holes.



Next, you'll need to drill the hole for the master cylinder. If you have an '84+ Bronco, the spot for the whole will be marked. However, do NOT drill the bolt holes. The ZF5 master is shaped differently and won't use them.



This does quick work. I can't remember the exact diameter (measure your master cylinder), but I believe it's a 1 1/4".





This is the earlier master cylinder with the bolt holes straight up and down.



This is the later (ZF5/M5OD) master cylinder with the bolt holes off-set.



I had to grind a small nick to get it to fit around the screw.



Install, mark, and drill.







Now that you're sure it's set up, pull it back out and finish up the bracket.





To get to the upper holes, you'll need to remove the cowl.



Good time to vacuum it out, too.



Lay the bracket in place and then work the bolts up gently from underneath. Once both are threaded, tighten it down.
Be sure to coat these in particular with RTV silicone to keep rain out.



The ones inside the engine bay are much easier to get to. Just put the bolts through and tighten down. This is easier since you can reach through the firewall hole and access both sides.



You know have a SOLID firewall.
 

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Discussion Starter #5 (Edited)
Slide the new pedal bracket up into place.



Slide the wire harness through the top hole and clip it back together. Bolt the pedal bracket down.



Reverse the rest to reinstall. Put the steering wheel back in and the dash back together. Reconnect the brake booster.
Bolt down the master cylinder, and connect the arm to the clutch arm on the pedal bracket assembly.



For me, I didn't have time to get a manual transmission column, so I just pulled out the pin and pulled out the shifter arm.



The next part is where things got tricky.
The later year trucks have the transfer case shifter coming out of the side of the transmission tunnel, and not out of the removable pan, like the earlier year models. I did NOT want to cut a hole in my floor for two reasons. I figured Ford reinforced this area for this new hole, and I didn't want cracks to develop in mine, and for two, I didn't want to leave a big hole in my carpet where the old shifter used to be.

So, I set about getting the original shifter to work with the ZF5.

It looked like it would be really close, but the biggest issue was the bolt. The NP-435 shifter I had had a standard thread bolt and the ZF5 bolt was metric. They were also marginally different diameters and lengths, which made them incompatible or would cause lots of slop in the shifter.









So, you can't just bolt the earlier year shifter to the ZF5 bracket.



Cut this nut off with a grinding wheel. Rest the wheel against the bracket itself to get a nice, straight cut.





Then, get a nylon locking nut and lock washer that matches the earlier year transfer case bolt, and crank it down tight. The shifter shouldn't have any slop, but should still easily rock (shift) back and forth.





Before:



After:



Now to get the ZF5 IN.



The ZF5 is tall, and even with my Bronco fully jacked up, I couldn't get it underneath while it was on the transmission jack.



So, I had to slide it under, rock it forward onto its front, and slide the transmission jack underneath it while it was under the vehicle.
The ZF5 is heavy (about 175 lbs), so get a friend if you feel uncomfortable with its weight.







Another technique I've heard of people using is to put an engine hoist through the door and lift up through the tunnel, but my garage doesn't have room to allow this.



Be sure the spacer plate is installed and then install the flywheel and pressure plate using the clutch alignment tool.



I had the motor mounts on the engine loose so that I could maneuver both. I think it might have ended up making it more difficult, but not sure.



It takes some finagling, but once it lines up right, it'll slide right together. I used some long threaded rod as guides with 1 or 2 on each side. It helped it to go on straight.

(And yes, that's a different engine than when I started. I also swapped out the 302 for my 300. ;) )





Bolt it down solid.





If possible, get a 5 speed crossmember from the junk yard, as it'll make life a lot easier. It curves back to accommodate the extra length.



It'll be marked as an M5OD crossmember (even on the ZF5 models).



Also, grab the drop down brackets for the sides, as they curve back, instead of dropping straight down. This will allow you to reuse the upper bolt holes, as they would a pain to redrill. The light, dusty brackets are the ZF5, and the rusty dark ones are the original AOD.





Bolt the transmission mount to the transmission.



Put the crossmember in place and bolt down the upper brackets all the way down. Rest the transmission bolts in place and then tighten them down. This will line up the crossmember.





(yes, it's upside down.)



Now that it's all lined up, you'll need to drill a single hole on each side for the crossmember hold down bolt.







Resting solidly in place.

 

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Discussion Starter #6 (Edited)
I had a transmission cover for my NP-435 but quickly realized it wouldn't fit. It hit the ZF5 before touching the floor.



The ZF5 uses a much taller cover, which I had grabbed from the yard with it.



I also found that the NP-435 shifter hit the side of the transmission tunnel opening.



This section needed to go:



I made sure the cuts were rounded on the corners, to prevent cracks forming.












Next, I cut a hole in the transmission tunnel cover.










I don't know why they did this, but this worked really well in my favor! The bolt holes on the original pan are directly across from each other.
On the ZF5 pan, they were offset, and the one on the driver's side was moved forward a few inches. This allowed me to put the hole forward (the original was where my cut is), so it all worked out perfectly.





All bolted down.



Put the lower boot cover onto the ZF5.




Carpet back in.



Cut a hole for the shifter. Make it as small as possible and work outward. You can't put carpet back in that you've cut off.





Seats and console back in.



You can buy ZF5 dust boots on line for a very reasonable price (about $60). They come with the boot and hold down bracket.

 

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Discussion Starter #7 (Edited)
Next, get the transfer case put back in.



I find it works best to tip it up and then just get it slid onto the transmission output shaft and it'll hang there.



Rotate it until the alignment peg catches and push it into place and bolt down the 6 bolts.



Precisely measure your front and rear driveshafts yoke to yoke, and have your current ones lengthened and shortened to match. The front will be longer and the rear will be shorter.













The transfer case shifter needs to be hooked up. On mine, I couldn't find an arm that was the right length, so I made my own.
To do so, I pulled the shifter back off and drilled and cut the peg that the arms normally clip to.





From there, I bolted on a heim joint.



I then used threaded rod and locking nuts connect it to the transfer case. It took a few sessions of pulling it out and cutting off more rod until I got the length just right. But once down, it worked beautifully with a smooth, satisfying shift.







Last step is the back up lights and the neutral safety switch.
The automatic plug has 4 wires.





Two of these make a complete circuit only when the transmission is in neutral/park so that you can start it.
You'll need to cut these and splice them together so they always make a complete circuit. The other two will need to be spliced into the reverse plug.





Last but not least, don't forget your fluids!



And don't forget you now have a clutch. :D


Have fun!
 

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Nice write up!

I'm one who has done the engine hoist through the door method. It works well using a strap on both ends of the trans.

While I was installing the pedals into my 96, I noticed a little crack in the firewall. So I crafted my own "stiffening" panel. I bolted it in a similar fashion, but I put some epoxy behind it to glue it on as well.
 
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Discussion Starter #10
Nice write up!

I'm one who has done the engine hoist through the door method. It works well using a strap on both ends of the trans.

While I was installing the pedals into my 96, I noticed a little crack in the firewall. So I crafted my own "stiffening" panel. I bolted it in a similar fashion, but I put some epoxy behind it to glue it on as well.
I'm curious what would cause the '96 to crack. The 92 - 96 body style came reinforced. Body flex from something else perhaps?

I can't imagine a reason anyone would ever need to take the plate out, so might as well epoxy it.

That does remind me though, be sure to put RTV around the bolt holes to keep rain out.
I'll add that to the write up. :thumbup
 
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It was even an automatic lol, so no clutch to cause the issue.

The truck was used for snow plowing in Kansas City for 80k, so I'm sure it hit plenty of curbs and such. Then it was a farm truck and had a gooseneck behind it. Remember the odd breakage on my c6 case? I'm sure it's all somewhat related to the plowing.
 

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I'll add another tidbit.

The zf5 (and maybe m5od) are known for the clutch master cylinder rod slipping off the pedal assembly pivot. I dealt with it on my 95 for a while. Theres a small white plastic bushing that holds the two together. Once the clips on it break, it will want to slide off.

To remedy this, I drilled a hole in the clutch pedal pivot stub and inserted a cotter pin to keep the rod on the pedal assembly. Never had an issue afterwards.
 
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Discussion Starter #13
Very good point.

Interestingly though, the original arm on mine had a hole already through it with a cotter pin in place, as did the new one I purchased. I wonder if they got rid of the hole later, thinking the clip would just hold it on?

This is another area of failure, simply because once the bushing wears out, people don't realize it. Then, they just keep grinding metal on metal until it's worn.
This puts a lot of slop in the pedal, and makes clutch engagement poor.

These aren't my pictures, but shows the worn pedal arm issue.



I made sure mine had a brand new bushing. I'm sure it'll be good for quite some time.



However, I would eventually like to purchase one of these and install it to eliminate the issue:

 
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I bought the kit on Amazon and replaced the plastic clip with a Hemi-joint mod. I absolutely love it.


Question for you Abandon.

I researched this to death around 2010. I started to price everything and search for a donor vehicle to swap out the automatic in the 1994. After a year I actually found the 1996 Bronco sitting on a lot for $3,200. I was still reeling from the gas price increase and since the re-gearing to 4:56 and the 35" tires... 9mpg was the best i could do in the 1994.

MAF... 5 speed transmission... manual locking hubs.... and a manual transfer case were just too much and I had to have the 1996. I do not regret the decision one bit.

How much did this cost in total? Just wanted to make sure I didn't totally blow it by just buying a new Bronco and not changing out the existing one.
 

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Discussion Starter #15
I bought the kit on Amazon and replaced the plastic clip with a Hemi-joint mod. I absolutely love it.
Was it pretty straightforward? Seems like it would be.
 

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Maybe my pivot stud had worn through the original hole? Not sure. Mine was bad enough that it wouldn't full depress the clutch safety switch and I had to reach down and pull the switch back so it would start.


Total cost for mine was pretty low because my zf5 had recently been rebuilt. Other than that, all I have to buy are the clutch system, because I dont want to use the one out of the donor. I paid 1800 for a running, but really rough 88 f250 with the zf5 in it. Adding up parts I can sell or want to keep, I can make every penny back. So I could technically have done the swap for a couple hundred, if I reused everything and sold off the parts from the donor. Only thing the donor couldn't provide was the pedals because it's an 88 and my truck is a 96.

Things I'm buying are flywheel, clutch, slave and master cylinder, and the fluid line. That's a few hundred bucks
 

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Great job man. Couple questions. Do you know how long that threaded rod ended up being for your transfer case shifter? Did you use a master cylinder for the truck the transmission came out of? I'm assuming the slave cylinder would be for a zf5. Also, what clutch did you use?

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Discussion Starter #18
Great job man. Couple questions. Do you know how long that threaded rod ended up being for your transfer case shifter? Did you use a master cylinder for the truck the transmission came out of? I'm assuming the slave cylinder would be for a zf5. Also, what clutch did you use?
The threaded rod was around 10" in length. I didn't measure it exactly. Just slowly cut off 1/2" pieces until it shifted really nicely.
It would change dependent upon which transfer case and transmission you had, since they have different linkages, shifter arms, etc. So it's better to just measure for your application.

I didn't use the master cylinder from the truck. I bought a fully pre-bled unit that included the master, hose, slave, and throwout bearing. Just allowed me to install and go, which was really nice. Part # AMS PS0726 from AMS Automotive

I don't recall which clutch I used. I just looked up an 11" clutch kit for a 1994 F-350 4.9L, and researched the different options until I was happy with the reviews, etc. :thumbup
 

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Great job man. Couple questions. Do you know how long that threaded rod ended up being for your transfer case shifter? Did you use a master cylinder for the truck the transmission came out of? I'm assuming the slave cylinder would be for a zf5. Also, what clutch did you use?

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Use the master and slave for your year of truck. Or the master and slave for the year of the transmission. Dont mismatch. Some years had masters and slaves available for both 4 and 5 speeds. They are completely different slave cylinders, and require different masters.
 

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Thanks guys. That's exactly the info I was looking for. I might be getting a 460 for free so I'm gonna start looking into that.

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