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AT to MT Swap

This page details the conversion of a 1995-1999 Eagle Talon/Mitsubishi Eclipse with 420A engine from an automatic to manual transmission. Pictures were taken of a 1995 car, so your car may look slightly different. This page is by no means comprehensive, but it will help the reader visualize the steps required for this conversion. You will probably get most of your parts from a junkyard, so we will start by showing pictures of the major components.

NVT-350 manual transmission with shift arms
Speed sensor with gear (probably installed on transmission)
Speed sensor plug with 6" of wire
Reverse sensor
Reverse sensor plug with 6” of wire
Three quarts of MOPAR MS9417 transmission fluid (not shown)

Clutch (preferably new)

Throw out bearing (new)
Clutch fork

Driver’s side transmission mount (The only real difference between the A/T and M/T mount is the height of the pin)

Rear roll stopper bracket (notice the difference between the A/T and M/T bracket)

Driver’s side transmission mount bracket

Shift cable bracket

Clutch slave cylinder

Flex line and clips
Lower hard line

Lower hard line bracket

Clutch master cylinder with nuts
Rubber line with clamp
Upper hard line
Bracket for upper hard line (not shown)
clutch fluid reservoir with cap, bracket, and bolts
Two 12oz bottles of DOT3 or DOT4 brake fluid (not shown)

Clutch pedal assembly with spring and bolts
Clutch interlock switch
Clutch interlock plug with 6" of wire

Brake pedal assembly with spring and bolts
Brake light switch
Brake light plug with 6" of wire

Shifter assembly with bolts and rubber bushings
Shifter boot
Shift knob

Shift cables with bushings and clips
Rubber grommet and plate (through firewall)

Gauge cluster from M/T car
ECU from M/T car of same year (not shown)

Now that you have all of the parts together, let's run though the removal of automatic transmission parts and installation of manual transmission parts. I will not go through every little detail. I am assuming that you are familiar with removing/installing interior panels and brackets.

Pull out the center console to expose the A/T shifter. Disconnect the brake/shift interlock, key/shift interlock, and shift cables. I think there is a light bulb for the shifter that must also be disconnected. Four bolts hold the A/T shifter assembly to the body. Remove those and the shifter should come out.

Here are the brake/shift interlock, key/shift interlock, and shift cables. The interlock cables run inside the car and can be easily removed.

Remove the cover around the steering column. Be careful as the bottom piece is bolted to the steeting column and the top piece is snapped into that. You should find a cable running into the key cylinder. Remove the screws and take off the cover. That will allow you to remove the key/shift interlock cable. Replace the cover using the screws. The brake pedal has the brake/shift interlock cable clipped to it. Unclip that and pull the cable off. Unhook the brake light switch plug from the brake pedal assembly. Remove the cotter pin and clevis pin that connects the brake master cylinder to the brake pedal. Unhook the return spring from the brake pedal. Remove the four nuts and two bolts that hold the brake pedal assembly in place. Pull the A/T brake pedal assembly out.

The shift cable runs through the firewall to the transmission. A rubber boot keeps water out. You will need to remove two nuts that hold a plate that holds the boot to the firewall. Move on to the transmission and unclip the shift cable. That should allow you to remove the shift cable from the car.

Now you need to drill holes in the firewall to allow installation of the clutch master cylinder. You should find that the sheetmetal on the interior side of the firewall already has an opening for the master cylinder. You need to pick a hole saw that matches this opening. Centerpunch and drill that opening. Now you can mark where the bolts should pass through the firewall. Centerpunch and drill those holes. The clutch master cylinder and clutch pedal assembly each have one stud. You put them together, sandwiching the firewall in between. Tighten the nut on the master cylinder as shown.

Tighten the nut and bolts on the clutch pedal assembly as shown. There should be one nut and two bolts on this side of the firewall. Insert the clevis and cotter pin to connect the master cylinder to the pedal. Hook the return spring from the pedal to the body. While you are down there, you might as well wire up the clutch/starter interlock switch. The clutch switch plug should have one solid black wire and one green wire with black stripe. Depending on what year and model car you pulled the clutch pedal assembly from, there may be one or two clutch interlock switches present. You only need to worry about the switch that gets its plunger depressed when the clutch pedal is pushed in. Run a 16-18 gage wire from the solid black wire on the clutch switch plug to a good body ground.

Run a 16-18 gage wire from the green wire with black stripe down to the starter relay and connect it to the small black wire with yellow stripe. The starter relay should be clipped to a horizontal metal bracket under the HVAC controls. Be sure you connect to the small black wire with yellow stripe as there is a large one on the relay as well. The clutch interlock switch wiring is required to start the car.

Now you can install the M/T brake pedal assembly. It goes in just like the A/T assembly you removed. Tighten the four nuts and two bolts as shown. Insert the clevis and cotter pins to connect the master cylinder to the pedal. Attach the return spring to the body. The plug for the stop light switch is the same between the A/T and M/T. Insert the plug into the stop light switch. If you forget this, you will have no brake lights and no cruise control.

You can install the M/T shifter assembly now. Make sure the rubber bushings on the shifter assembly are in tact. Replace any damaged ones. Tighten the bolts as shown. Run the two shift cables under the HVAC/Radio and out the pass-through in the fire-wall. Seat the rubber boot in the pass-through, install the mounting plate, and tighten the nuts. Clip the cables into the base and fit the cable ends over the pins on the shifter arms. Make sure the bushings in the cable ends are in tact. Insert the cotter pins and bend them over. You should probably resist the temptation to put the center console back in and cover up the shifter assembly. Move out to the engine bay.

Start by unplugging the electrical connectors on the automatic transmission. Don't cut the wires up yet. Just pull them out of the way. 1995 connectors are shown. Be aware that the 1996-1999 cars combine the park/neutral position switch into the transaxle range switch. You should also remove the battery and battery tray. Your airbox, intake pipe, and anything else above the transmission needs to come out.

If the car isn't already on jack stands with the rear wheels chocked, do it now. Get under the front end and loosen the through bolt on the front roll stopper. Loosen the four bolts that hold the center support member and pull it out. It is smart to leave one bolt loosely holding each end until you are ready to remove the complete center member.

Remove the front wheels. Then, remove the bolts on the lower arms of the front suspension. Also remove the through bolt on the damper fork.

Now you should be able to swing the front hub/spindle assembly out to lightly pull on the axles. Now would be a good time to drain the fluid from the automatic transmission. You can do this by cutting the rubber lines on the transmission cooler and letting the fluid run into an oil pan.

Use a pry bar to pop each axle hub out of the transmission Push the axles out of the way. You do not need to remove them as they will work with the manual transmission.

Remove the two small brackets joining the engine to the transmission. Then, remove the bolts holding the access cover to the transmission and remove it.

This exposes the flex plate and the bolts that hold it to the torque converter. You can put a box end wrench on whichever bolt head is accessible and strike it with a mallet. That should break it free. Remove the bolt and turn the engine over to the next bolt. You can turn the engine over by turning a cam bolt or the crankshaft bolt clockwise (tighten).

Before removing any more bolts, support the engine with a jack. A piece of wood between the jack and oil pan will keep you from causing damage. Loosen the starter bolts and remove the starter. Remove the remaining bolts holding the transmission to the engine. At this point, the transmission should be hanging by the rear roll stopper and driver's side transmission mount. Loosen the bolts on the rear roll stopper bracket and remove it.

Assuming that you don't have a proper transmission jack, put a hydraulic jack under the automatic transmission. You can stack some boxes under the transmission to lessen its impact when it falls.

The transmission is balancing on the hydraulic jack underneath. If you wish to control its decent, you can use a ratchet strap pulled around a strut tower bar and anchored to something heavy (like a work bench). This is a good idea because the automatic transmission weighs a good 125 pounds. When you are ready to drop the transmission, remove the bolts on the driver's side mount.

Alternate between lowering the hydraulic jack and loosening the ratchet strap until the transmission is down on the ground. Stuff clean rags in any open holes to keep fluids from leaking out (referring to the transmission only).

Your engine bay should look something like this now. If not, then you should probably re-read the last few steps about the whole "removing the transmission thing".

Let's move back to the clutch master cylinder. Loosely install the upper hard line. You will probably need to remove the ECU, TCU, and their bracket to fit the upper hard line. Make sure the bends match the contours of the body. You can correct the bends by hand. Tighten the nut into the body of the clutch master cylinder as shown.

Fit the rubber hose from the clutch master cylinder to the reservoir. Don't forget the spring clamps. Bolt the bracket to the firewall as shown.

Move down to the other end of the upper hard line. Bolt the upper hard line bracket to the body and clip the flex line into the bracket. Tighten the nut to the flex line as shown.

Drag out the manual transmission and make sure it has the driver's side transmission mount bracket and shift cable bracket installed. If not, install as shown. If the speed sensor is not installed, do it now. Whenever messing with the speed sensor, be careful not to drop its gear into the transmission (you might never get it back). Ignore all of the crazy wires and micro-switches on this transmission as their purpose is completely none of your business.

Lubricate the new throw out bearing and install it with the clutch fork on the transmission input shaft (lubricate this as well). A black moly lube is OK to use. Be careful not to break the tabs on the new throw out bearing (they can be delicate).

Slide the new clutch and flywheel assembly onto the transmission input shaft. You may want to install a dust cap in the center of the flywheel (taken from a stock flywheel).

Now you can start installing the manual transmission. Balance the transmission on the jack and raise it up into the car. You can do this fairly easily because the manual transmission weighs half of what the automatic one does. Line up the transmission with the engine and install the upper bolts. Torque them as shown. Install the starter and torque its bolts as shown. Get under the car and carefully torque the two lower bolts as shown. Position a jack under the transmission and remove the jack from under the engine. Lower the engine/transmission to slip the driver's side transmission mount onto the transmission. Leave the nuts loose and raise the engine/transmission up to engage the mount with the bracket on the body. Torque the nuts on the driver's side transmission mount and slide the through bolt in. Thread the nut on loosely for now.

If you removed the rear roll stopper mount, bolt it down to the body as shown. Install the rear roll stopper bracket on the transmission and bolt it down as shown. Use a pry bar to line up the rear roll stopper bracket with the mount until you can push the through bolt in. Go ahead and torque the through bolt as shown. Once you do that, you can move back to the driver's side transmission mount and torque its through bolt as shown in the previous image.

Now, you need to bolt the flex plate up to the flywheel. Remember that one of the bolt holes is offset. Loosely screw one bolt in and spin the flex plate to see if the other bolt holes line up. If they line up, screw the bolts in and torque them as shown. If the bolt holes don't line up, remove the one bolt and rotate the flywheel to the next hole. Loosely put the bolt in and check to see if the other holes line up. For extra security, you could put some blue loc-tite on the bolts before finally torquing them.

You can install the axles into the manual transmission now. Twist the axle to line the splines up and push the end into the transmission until the C-clip snaps into the differential. Make sure the oil seal on the transmission seals against the machined shoulder on the end of the axle. Bolt the lower suspension arms into the body and torque the bolts as shown. Install the through bolt that attaches the damper fork to the lower arm, but do not fully tight the nut. Now you want to pull the car off of the jack stands and support the weight of the car on the driver's and passenger's side knuckles. You can stack up some blocks under the knuckle to support it. You would like to have the height of the car similar to the normal ride height. It would be wise to keep a block under the front jack points. This will support the car is the knuckle somehow falls off of the blocks. You wouldn't want the car to come crashing down possibly crushing you. Now tighten the nut to the torque shown. You can now put the car back on the jack stands and put the wheels on. If you want to see the axle/suspension instructions in more detail see the axle page.

Bolt the lower flex line bracket to the transmission case. Use a clip to attach the flex line to its bracket. Loosely thread the nut of the lower hard line into the flex line.

Move back to the transmission to install the clutch slave cylinder. Put a little grease on the rod end and fit that into the clutch fork. Tighten its two bolts as shown. Loosely thread the nut of the lower hard line onto the slave cylinder. Now, tighten the nuts on both ends of the lower hard line. Loosen the bleed screw on the clutch slave cylinder and put a long piece of clear hose on it. Stick the end of that hose into a jar of brake fluid. Fill up the clutch reservoir with some of the same type brake fluid. Get in the car and slowly pump the clutch pedal, letting it back out slowly as well. Check the level on the clutch fluid reservoir and top it off. Keep pumping the clutch pedal and adding fluid until you are pushing clean fluid with no air bubbled out of that clear hose attached to the bleed screw. Once you are certain that all of the air is out of the system, tighten the bleed screw and remove the hose. Top off the clutch fluid reservior again.

You might as well install the center member now. Thread the four bolts in and torque them as shown. Install the through bolt on the front roll stopper, but do not put the final torque on the nut. Wait until you have the car back on the ground. While you are down there, you can fill the transmission with oil. You may wish to tape a rubber hose to a small funnel to get the fluid in the filler hole. If you can't get the fluid in the filler hole, you could also remove the reverse sensor and dump the fluid in there. You need to keep adding fluid until the level is 4mm (0.157") below the filler hole or higher. When you are done, put the filler plug back in.

You can move back up to the top of the transmission now. Clip the shift cables into the bracket on the transmission. Slip the ends of the shift cables onto the pins on the shift levers. Install the washers and cotter pins to secure the cables.

You need to wire up the speed sensor for the manual transmission. The diagram above shows the speed sensor. You need to wire up the speed sensor plug to connect those pins to the correct wires at the ECU and TCU. The pin locations at the ECU and TCU changed over the years, so you should just follow the wire colors. Tap into the wires at the ECU and TCU instead of cutting them off. It would be wise to solder and wrap these connections.

Now you can wire up the reverse sensor for the manual transmission. The diagram above shows the reverse sensor. Wire up the reverse sensor plug to connect those pins to the correct wires on the old park/neutral position switch plug (1995) or transaxle range switch (1996-1999). Cut the park/neutral or transaxle range plug away and connect directly to its wires. It would be wise to solder and shrink wrap these connections. If you have a 1995 car, you should have also have a back-up light relay. The reverse sensor provides power to the coil of the relay when engaged, but you also need to supply ground to the coil of the relay (the TCU did this previously). Find the white wire with red stripe on the 60 pin connector for the TCU. Cut it away from the connector and connect directly to the black wire from the transaxle range switch connector. For the moment, I suggest you resist the urge to cut away all of the old TCU wiring that is unused. You can come back and clean that up after you complete the swap and test everything out.

Head back inside the car and test out your installation. Push the cluch pedal in and move the shifter to select each gear. Try every gear a couple times to make sure they are engaging fully. If any gear won't engage, start checking over the shift levers, cables, and bushings. If everything feels good, install the shifter boot, center console, shift knob, etc.

Go ahead and swap out the gauge cluster now. Two screws secure the trim piece around the gauge cluster. After removing four screws, the A/T cluster will pull straight out. Reverse this proceedure for the M/T cluster.

Take the car off of jack stands and put the wheels back down on the ground. Squeeze an arm under the car and try to torque the through bolt on the front roll stopper. If you can't squeeze under there, you can raise the car up and slide a block of wood under each front wheel. Set the car down on that wood to give you the necessary space to torque the front roll stopper, while maintaining load on the suspension.

One of the last items to swap out is the ECU. There is one bolt holding the plug to the ECU and three screws holding the ECU into its bracket. If you chose a M/T ECU that is from the same year as your A/T ECU, it should plug right in. You are now free to install all of the components that you removed to get at the transmission. That would be the battery tray, battery, intake pipe, airbox, and vacuum hoses. Once you have everything reconnected, take the chocks from behind the rear wheels, and get in the car. Turn the key to "ON" to prime the fuel pump, depress the clutch pedal, and try to start the engine. If it starts, move the shifter to neutral and let the clutch out. Allow the engine to warm up and give the ECU some time to smooth out the idle. Check over the engine and make sure you installed all of the hoses and tightened all clamps. If everything checks out, take the car for a test drive. Be easy on the clutch and try not to slip it any more than you have to. Try out every gear, including reverse. You need to break-in the clutch before you really beat on the car. A good way to do that is driving in "stop and go" traffic for a few weeks or 400 miles. You want the maximum number of clutch engagements, without overheating the friction surfaces.

Contributed by Corbin

Cars Modifications Control Transmission AT to MT Swap

Document statistics: Last modified on 2013-03-10 15:32:09 by Corbin

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