The nationwide coverage offered by Certified Transmission at our 5 Omaha shop locations is among the best in the transmission repair industry. Our 5 Certified Transmission shops in Omaha proudly stands behind the work performed by our transmission specialists with a standard 3 year/100,000 mile warranty on all replacement automatic transmissions. Also known as 46RH (A518); 47RH (A618); 46RE (A518 electronic governor); 47RE (A618 electronic governor) Versions of this transmission were used from 1990-up. An electronic governor was introduced in 1997. 1992–2003 A518 (46RH/46RE) — 4-speed automatic; 1994–2003 A618. (for list of transmission used in AMC vehicles before Chrysler buyout) References.
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28 minute read
727 to A518 swap a novice guide
Compliments of 360FISH @ www.cuda-challenger.com
5-7-2012
I love my 73 Fish but was getting really tired of having my muscle car passed on the FWY while screaming along at high RPM. Besides the embarrassment, it was a source of anxiety having my engine wind up for long periods. So much so that I wasnt straying too far from home. I knew I needed to change something.
This write-up is intended to supplement the materials others have shared on this swap. My hope is to give some insight into the swap from someone with no experience doing something like this. This write-up is from notes and memory and if something seems out of place or unsafe, then dont do it with out getting help first. I intend to keep this updated so let me know if you have something to add.
References
The grand daddy thread. I owe a lot to the folks who contributed to this thread!
For the big block guys:
The PATC write-up is required reading if you want to automatically control the A518 OD and lockup.
My mentor on this swap (and anything Mopar) is Rory Fontana. His advice and support helped me get through the process successfully. Rory is truly passionate about these cars and was invaluable in his advice, hints and tips. The cross member fabricated from my templates is available through him if youre interested.
Rory Fontana
Fontana Motor Sports. (818) 641-3512.
[email protected]
More information on how the cross member was built can be found here.
Its just nuts & bolts (you can do this)
The ultimate goal
Configure the car for long trips, maybe a Power Tour someday.
To do this I knew I had to change out my trusty 727 for something that would give the Fish more legs without costing an arm and the other leg. An overdrive tranny was the ticket and I looked at everything before deciding on the A518.
Why the A518?
Low Cost! The 518 is widely available at good prices. I have a small budget.
Manual trannys need more parts ($$$) and modifications (the 4-speed hump)
Keislers automatic is great, but really expensive.
Other automatics need more in the long run to get them installed.
Skill level I cant weld or do body modifications.
Skill level - I can wrench (Its all just nuts & bolts) so I want low complexity in the swap.
The transmission bolts right up to my 360 small block
If you get the early A518 you can keep your non-lockup torque converter ($$$)
The over drive provides a 31% reduction in RPM
No modifications to the Cuda are required to make the swap work.
Which A518?
The A518 is also called the 46RH (hydraulically controlled) and the 46RE (electrically controlled).
You want to find the 46RH. The 46RE requires computer control and is beyond the scope of what I wanted to tackle.
The 46RH is broken down into the early 2-pin non-lockup (1988? Thru 1992?) and later 3-pin lockup versions (1993 1995). You can find the 46RH on Dodge vans and trucks (wt. the V8). The electronic 46RE started in 1996.
I found mine on Craigs list (a 1990 non-lockup 46RH), but realize now I could have saved money pulling one at Pick a Part (junkyard).
The non-lock-up allows you to use your existing 727 torque converter. This is not true of the lock-up version. This is a cost savings I wanted.
Precautions
The A518 is significantly heavier than the 727. Dont try to do this with a standard floor jack you could hurt yourself doing that. I bought a tranny jack from Home Depot because the adjustment knobs looked beefier than some of the other ones. Youll need them. It worked out great.
Dont try to rebuild the OD section of the A518 unless you know what youre doing. There is a spring loaded to 800 lbs that can seriously hurt you.
You need to get the car up really high on jack stands to do this. Get nice heavy jack stands and find other safety backups I use tree stumps and ramps.
If you go to junk yards (and I hope you do theyre one of my favorite places to go now) be sure to check that the vehicle is safe to get under. Ive seen some precarious setups give the body a good shake to confirm its okay.
What you need Approximate cost
The A518 $150 (core) on up
Mine was about $550 with a rebuild
3/8 cooler lines $ 5 at u-pick-parts
Cooler, hoses, brackets, fittings* $ 80 B&M Super Cooler
Simple wiring & switch to control the OD. $ 15 (lots of options here)
Shorten the drive shaft 2 to 3 inches $ 75 (Wenco in Van Nuys)
Custom plate to hold the shift rod in place $ 20 (or part of kit below)
A new cross-member to hold the tranny $300 (see Rory)
GM style tranny mount $ 8
Tranny fluid (10+ quarts) buy more!
Your 727 shifter/kick-down arms & linkages
Oil filter (unless yours comes off easier than mine)
Notes:
I found my A518 on a local craigs list. Honestly I would have saved money going to a local Pick-a-part and pulling one there the having it rebuilt. Ive gotten use to junk yards since starting this project and its a no brainer now.
fittings may already be on the lines you grab. See the cooler lines & cooler section.
Details
Jacking up the car
May seem simple but I didnt know to place the jack stands under the rear axles This is desirable when dealing with driveline angle later. (?) You need to get the car way up to fit the tranny and its jack under the car. (I wish I had a lift) With the tranny on the tranny jack I measured the height of the bell of the transmission. You need to be about that high to make this work, though youll be able to tilt the bell down to help with clearance. (and to get the 727 out!)
I had to disconnect the exhaust at the collectors (both sides) so it would free up wiggle room.
This is the general order in which I disconnected the 727. Drive shaft off, neutral safety switch & lines disconnected, linkages/brackets removed. (see the note below about measuring the driveline) Then supported by the tranny jack, torque converter bolts & starter, rear tranny mount and cross member then finally bell housing bolts. I hate the bolt that sits behind the oil filter!
Bring the 727 down slowly checking for anything that might catch on the tranny on the way down. Go slowly and check all around. You should secure the tranny to the jack before going further. Slide the tranny back and out tilting the bell down as needed to clear I was able to keep the bell in the tunnel with the tail coming out toward the side of the car. Tilting, sliding, tilting more, tugging on the exhaust, etc.
Measure the drive line!
Before taking the 727 out measure the distance from the transmission tail housing to the rear end. Youll want to do the same measurement after the A518 is installed to help determine how much you need to shorten the drive shaft.
You should also measure the angle of your valve cover (fore & aft) as an indicator of engine/transmission alignment when the A518 is put in place. Rory turned me on to iHandy-level a free app for my Android (iPhones too). It gives you angle of inclination which is cool!
I did not make these measurements before hand and had nothing to go by later. I think I lucked out in the end and dont seem to have a real problem.
Tranny modification
After removing the 727 I rolled the A518 into place and lifted it up to be sure where I wanted to cut the notch for clearance up into the tunnel. I marked the case and gave a little extra clearance in case things shift one way or another. This matched well with the pictures from other folks who did this swap (see references).
I rolled the tranny back out from under the car for the impending surgery.
I have never done anything quite like cut up a tranny case before. After reading plenty of information on the web I bit the bullet and went for it. I used a Rockwell Sonicrafter to cut the case. It works but was very slow doing it. That might actually be a good thing seeing as it gave me time to react to what I was doing. Anyway, there are much better tools for this Im sure.
This process makes a mess, with aluminum flakes getting everywhere. Its a good idea to mask holes in the tranny and prep your area with a drop cloth. Wear an mask and eye protection!
I only needed to cut the two notches noted in the section above. I should have cut the notch for the shift rod more flush with the case. That little lip I left has been a pain in the rear (catching on the shift rod) when trying to get the tranny up into place.
Cooler lines & cooler
The steel lines from your 727 are too small so you need to get 3/8 tranny lines. The 3/8 tranny lines can be found CHEAP at the junk yard in 1990s Dodge vans and trucks that had V8s and A518s. Dont be put off by the thought of going to the local junk yard. Ive come to love it! Its a real treasure hunt. Just be prepared to sacrifice the clothes you wear, and cover the seats in your car, etc. Go with a buddy, its fun and wear latex gloves seriously
The lines you find will clean up real nice with a little brake cleaner and fit the contour of the engine perfectly. Dont get the Jeep ones that run to the right of the engine I bought some and thought they would work, but they didnt quite fit. Also, if you find that one of the lines has a one-way flow value, remove it.
Youll find yourself trying to bend the tranny lines to snake them around the engine. Be patient and youll find a way to get them there. I recommend you fish them through before you put the tranny in. If you need to bend them be very careful use a hand held tube bender I dont think theyre too expensive.
The lines will ultimately go to a cooler you mount somewhere up front. The A518 needs a really good cooler to keep fluid temps reasonable. I have been advised NOT to run the tranny lines to the radiator cooler because the fittings are smaller than 3/8 and will restrict flow. Get a separate cooler.
I bought a decent B&M cooler for about $50 on Amazon. I was later told that early 2000s RAM trucks had a really nice cooler that would fit a 26 radiator frame. Ive seen them and Im envious I may swap mine out if I see another one at the junk yard.
Mounting the cooler was a pain in the tail and will be different for everyone based on the cooler being used. I ended up getting some U-shaped brackets off the front of Jeeps and mounting mine to that. Works and doesnt look too bad either.
Youll need 3/8 rubber transmission hose to link the cooler to the transmission lines. I bought 10 cheaply enough at a local AutoZone.
Heres a trick regarding fittings the steel lines you find might already have hoses on the end. One of mine had a hose already attached but had a fitting I didnt want to deal with. You can grind/cut off that hose and expose the steel line underneath. You might need to flare the end then just slip the rubber hose over that end with a hose clamp.
The other line had a flow valve and the same type of hose connected to the valve. I removed the valve Im told you dont want it but that left me a steel line with a flared end and a nut on the end simply slide the nut back and slip the hose over the steel line and use a hose clamp to make it secure. Ive had no leaks.
I discarded this
I should have bent the hose enough to slide the nut back more no fitting needed.
The other line end after taking off the connected hose (sorry I didnt get a before picture)
Wiring the beast
Note 1: My tranny is the non-lockup version and has a two pin OD socket. Later units will have a three pin socket to wire up. There are two pins in the yellow socket
Note 2: Im using a manual toggle switch to control the OD unit. I decided to wait on trying to use pressure switches. So far Im really happy with this setup.
You need to find a two pin plug to fit the socket on your transmission. I found them at pick-a-part on 1990s (maybe newer?) jeeps and dodge trucks. They are used to plug in fog lights and other electrical at the front of the truck. Get as much length of the wire as possible and cut it. I bought two for a $1 each!
To control the OD unit you need an ignition switched source which runs to the positive side of the OD plug. Luckily you have one about 6 inches away in the center wire of the three wire neutral safety switch. Splice into that middle wire and run it to the positive side of the plug.
On my car it was really easy to unplug the neutral safety switch and unplug the other end at a socket sitting a few feet away up along the body toward the engine bay. I took the wiring assembly inside and worked on it there. Be sure to splice far enough away from the plug to give yourself room to fix errors. Its best to solder these splices.
The negative side of the plug should be extended to run the length of the wire assembly and terminate at the same place the rest of the assembly terminates. Crimp on a connector at that point.
The ground wire will ultimately run to a ground to complete the circuit. This length of ground wire will be where you put the switch. When the switch is on, you have a circuit running to ground which allows the positive wire to feed power to the OD unit.
Both plugs in place
I ran about 5 feet of wire from the ground wire connector (the assembly you spliced into) up through the firewall at a point near the parking brake and fished it under the carpet toward the console. The console is easy to remove (3-4 screws) revealing a spot directly in front of the shifter where the wire can be fished up along the front of the shifter rod that supports the T-handle. If you bring the wire thru the side of the shifter it will get caught up in the mechanism, not allow you to put the shifter all the way in park and damage the wire (doh!).
The idea is to have this wire connect to a switch on the T-handle and from the switch the wire will terminate to ground connected to the screw that attaches the T-handle to the shifter. (I did need to find a slightly longer screw) The dang thing works too!
I set it up so I could disconnect the T-Handle wires using simple connectors. Some day Ill solder these for a cleaner look. I used 16 gauge wire for thisended up using red wire when I should have run black, etc. just because
Shifter (T-Handle modification)
Take your T-handle off the car and take it apart. Mine was practically falling apart anyway so this way easy.
The Radio Shack mini toggle fits a space in the right front of the handle without having to widen anything inside. Find a drill bit that fits (Radio Shack says hole) and carefully make a hole out the front of the handle. The switch should stick out through the hole enough to thread the included nut on to hold the switch in place. Mine would only do so if the switch was up one way vs. the other just turned it over.
SPST High-Current Mini Toggle Switch Model: 275-324 $ 3.19
The switch sits between my right pinky and the next finger in and toggles left/in (on) to right/out (off). Not up or down, which would be odd.
Once that is set, remove the switch and solder a short piece of wire to each terminal on the switch. You might want to carefully bend the terminals on the switch away from each other to give a little room for soldering. On of these wires will connect to the screw at the base of the handle (crimp on a round connector) so give it only that much length, The other will connect to the wire coming up from the front of the shifter. (see previous section on wiring).
You will need to open up a small gap at the bottom seam of the T-handle to make room for the two wires to exit the handle. I made the hole in the back half piece of the handle because the wires would exit there more easily. People have mentioned that using ribbon cable would be better for this maybe next time.
I did not solder the connections as I wasnt sure it was going to work. Once it was all working I simply wrapped the T-handle in electrical tape. Someday Ill come back and clean this up and wrap the handle in leather, etc.
Ugly - yes
Wrapped to hide the ugly
This switch has worked better that I ever dreamed so far. It is easy to use but small enough most people dont see it and it really fits my hand well. Pretty cool for a cost of $4.
Putting the transmission in the car
Be patient
Always be aware of the shift rod sticking down in the way of the tranny as you maneuver. I have accidentally shoved that rod up into the car a few times because I jacked up the tranny without realizing it was caught up. Ive had to hammer the dang thing back down : ( Go slowly and check all around.
Get the tranny lines routed around the engine (but not hooked up yet) before putting the tranny in.
Dont forget the torque converter when putting the tranny in. Some people put it in place and hold it with something (?) across the bell housing. I slipped it into place under the car
The engine will be sagging with the tail end down. Line up the tranny guide posts and get those bottom bolts in place to help keep things together. Make use of the tranny jacks adjustment knobs and get the rest of the bolts in place.
Once the bell housing bolts are in place, ignore the torque converter bolts for now you want to be sure the tranny is going to fit and might need to pull it again those torque converter bolts are a pain and take a lot of time to deal with. Just dont forget to connect them when you are happy with the placement of the tranny!!!
Linkages and tranny lines are the last thing to worry about. You dont want to be hooking these up before you are sure everything (engine, tranny, drive shaft, rear end) lines up correctly.
Before I had my cross member built I relied on the tranny jack to hold the tranny in place. I found that overnight the tranny would sag. My regular floor jack would too. For this reason dont hook up any linkage, lines, etc. and leave them connected over night. Dont want to pull/bend things and cause problems.
The tranny should raise up into the tunnel pretty far but should not touch the tunnel. The closest spot to the tunnel I could see was the lug (?) on the upper passenger side. I clear it with about a inch to spare.
Connect the GM style rubber mount to the bottom of the tranny. The bolt holes need to be lengthened toward the center of the mount to fit the spacing of the tranny bolt holes.
Put the speedometer line on now it just barely clears and youll need to jimmy the transmission a little to get the cross member on but it should squeeze in.
Get the cross member in place and determine how many shims you might need (this assumes you use the cross member I did). I used three 1/8th shim plates. The bolts I used to mount the tranny came from donors at the junk yard.
Its time to measure for the drive shaft shortening
Drive shaft modification
I measured a 2.5 inch difference in the length of the two transmissions. I didnt trust my measurement and had the drive shaft cut 3 because I had read somewhere else they had shortened their even more. This turned out to be just fine, though 2.5 would have been better.
I learned that you dont want the yoke to be too short when sticking into the transmission. The further out the shaft is the less there is to grip and drive angle issues magnify against the rear bearings in the tranny causing them to wear/fail.
For those local to Los Angeles I took my drive shaft to Wenco in Van Nuys CA. Very reasonable and quick turn around.
Drive-line angle
This was a crap shoot for me and I think I lucked out.
I learned that you can measure the angle of the valve cover fore and aft and keep it up to about 3 degrees. Mine ended up at 4 degrees but its working.
A518 4x4 Transmission
I also measured the angle of the yoke and of the drive shaft and anything else I could figure out
Get the cross member in place and start to work out the drive-line angle, shimming as needed.
Linkages, lines, shifter
I used all of the linkages I previously had on my 727. I had to swap the two shifter levers on the 518 with the ones I had on my 727 to make this possible.
The levers on the left side of each pair is from the 727. Very similar but the A518 levers didn't fit the linkages.
There was not a lot of room for the back cooler line and the shifter linkage (from the shift rod to the arm on the tranny). I got the cooler line figured out first and had it bend up as close as possible to the floor pan so the linkage will work underneath it. Be really careful not to cross thread the cooler fitting. Its easy to do and I had to replace one. Sigh.
I secured the shift rod with the bracket I designed and start working on the linkage to ensure clearance. My son sat in the car and worked the shifter for me so I could ensure full throw in the linkage from Park to 1st.
Misc:
I learned a lot from Rory when getting things up and running again. I never understood what the kick-down linkage really did. I thought it had something to do with flooring the motor and having the gear kick down to handle it well its more important than I thought.
To get the most out of your transmission and to save it from premature wear you need to be sure the kick-down linkage is correctly configured. Its really a pressure valve which works against the throttle pressure (?) to determine the correct time to shift. When correctly setup you get the maximum out of each gear before the shift (there are other factors too) but if its not setup (or missing) you will foul things up in the tranny and can burn a your band and lose a gear. A friend of mine didnt have this connected and lost shifts to second gear.
Its a good idea to prop up the motor (block of wood and a jack) on the back half of the oil pan if the tranny is going to be out for a while.
If you still have the old fashioned boat anchor starter, now may be the time to replace it with a smaller high torque version. I found mine at (you guessed it) the junk yard for $11 and it works great!
Its just nuts & bolts (you can do this)
The swap in a nutshell
A518 Transmission Manual
Two notches are made in the transmission case.
These are simple modifications and do not effect structural integrity.
This notch allows the transmission to fit up into the tunnel.
Looking up from below note the clearance.
Notch here to make room for the shift rod
I should have smoothed this out closer to the case. That lip has been a pain.
The steel bracket holds the rod in place. You need to fabricate this piece unless you can find something.
The cross member holds the transmission in place.
This is the key to making the whole project work.
Its designed to provide adjustment for fit.
I'll add more here...
Talking to Rory tonight about the non-lockup vs lock up... He suggested controlling the 3-pin lockup version with the same switch as the OD. Seems like a good idea to me and simple to add to the wire harness suggested in this write-up. I'd be interested to know if anyone has tried it.
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