AOD to T5: A 12 Step Program

I originally purchased my 92 GT with a bad AOD, with the intention of dropping in a DOHC modular motor and 4R70W transmission. To get the car going as a short-term solution, I was going to have the AOD rebuilt on the cheap. When a “friend-of-a-friend” deal went south and the jackass disappeared with my AOD and his cell phone was cut off, the car ended up sitting. After I decided to unload my CP autocross project, I realized I still wanted something I could autocross. Considering the parts I had lying around, making the GT an ESP car, as uncompetitive as it might be, was a great low-buck solution. The first step was to get the GT back on the road, but now with a T5 rather than the originally planned modular swap.

My original plans in writing this article were to make it a very complete AOD to T5 swap guide. But that was before I found this site. Not wanting to recreate the wheel, the focus is on the particular issues I faced, along with an overview of the swap. Besides, if you really need every nut and bolt covered in detail, you probably should have someone else do the swap.

Parts

  • transmission
  • bellhousing
  • flywheel
  • pressure plate
  • new flywheel bolts
  • pilot bearing
  • throw-out bearing
  • new rear main seal (optional)
  • clutch fork
  • clutch cable
  • clutch alignment tool
  • manual pedal assembly (with neutral safety switches and quadrant)
  • manual transmission harness
  • shifter and knob
  • lower shifter seal (generic aftermarket piece)
  • shifter boot and manual trim panel

Doing an AOD to T5 swap consists of 2 main parts; inside the car, and outside the car. I decided to start inside the car because I wasn’t in the mood to get greasy.

Part 1: Inside the Car

Step 1: Drop (and Remove) the Steering Column

The first thing I did was remove the two front seats and drop the steering column. The column needs to be dropped in order to swap the pedal assemblies. I’ve read that it can be done without dropping the column, but I’ve also heard and read that its much quicker and easier if you do. After doing the swap, not only would I drop the column, but I’d completely remove it.

Before dropping the column, the column harness needs to be disconnected. I used a small flat-head screwdriver to help pull apart the harness connectors, but you could do it without. Go gently here, or you’ll break the plastic clips that hold the connectors together.

There is also another component that needs to be disconnected before you can remove the column; I believe it’s called the shift lock actuator. What this component does is prevent you from shifting out of Park without pressing the brake. Without the AOD, you don’t need this. The cable coming out of the bottom of the mechanism attaches to the shifter.

Step 2: Remove Pedal Assembly

Before you can start unbolting the pedal assembly, you first need to disconnect the brake booster rod and brake light wiring from the pedal assembly. It’s easy enough to do, just make sure to take note of how it fits together so you don’t have any problems when installing the manual assembly. With the column dropped, there should be 4 remaining bolts on the firewall holding the pedal assembly in. I was able to get to all 4 using some long extensions, and it really wasn’t too bad.

After everything is unbolted and disconnected, take a break if you’re short on patience. Taking out the pedal assembly and putting in the new one can take a little while. Of course I dropped, but didn’t remove my steering column. If the column is removed, it should go a lot easier than it did for me. Pull the front of the assembly down first, as it mounts to 2 of the steering column bolts (which were removed when the steering column was dropped), then pull the assembly away from the firewall.

Step 3: Speedometer and Clutch Cables

The speedometer cables on automatics are routed through the hole the clutch uses on the manual equipped cars. You’ll need to pull the gauge cluster, disconnect the speedo cable, pull it through the firewall, and feed it back through the appropriate hole. This hole is slightly higher and to the left (when looking at the firewall from the engine compartment) than the hole the speedo cable came out of, and that the clutch cable will use. My car has a large power cable going through the speedo cable hole, so I used an existing slit in the steering column seal for the speedo cable. At some point I’ll rewire the stereo, and will correctly route the speedo at that time. The clutch cable can then be routed through the firewall. Using a little lubricant can help ease fitting the grommets into the firewall. Reattach the speedo cable to the gauges and you can screw the instrument cluster back into the dash.

Step 4: Install the Manual Pedal Assembly

When searching for a used manual assembly, I was told the housings were the same, and that you could just bolt a clutch pedal up and be done. Not so. There is a tube through which the clutch pedal mounts that is nonexistent on an automatic pedal assembly. Not to mention a complete pedal assembly will get you the electrical switches for the clutch to correctly activate the neutral safety switch, and a clutch quadrant if you’re not planning on upgrading.

The factory clutch quadrants aren’t very good and are commonly upgraded. However, because I plan on autocrossing my car in E Street Prepared and class rules don’t allow this upgrade, I reused the factory quadrant that came with my assembly.

I was able to install the manual pedal assembly by reversing the way the other one came out. I fit the bottom two firewall bolts first, then lifted the front of the assembly up onto the other bolts. Install the nuts on the firewall, then attach the clutch cable to the quadrant, and hook up the brake booster rod and brake light switch.

There are a few extra electrical connections to hook up for the clutch. These wires were installed, but jumpered, from the factory. There are two jumpered pairs behind the left kick panel (actually, only one of mine had a jumper), and a third jumpered pair behind the stereo and center console. Simply unplug the jumpers and plug them into the pedal assembly.

There’s one ting left to set on the pedal assembly. There’s a little plastic clip on a plastic rod that sticks out the back of the neutral safety switch. Slide the clip all the way up snug to the back of the switch, then press the clutch pedal to set it at it’s proper distance. When you press the clutch, the clip contacts and pushes in a tube that goes around the plastic rod. When this tube is pressed in, it activates the switch. I initially didn’t set this, so the switch wasn’t working, and made me believe I had a short.

Step 5: Install the Steering Column

The column goes in just the way it came out. Install the column, then hook up the column harness connectors. However, don’t reinstall the dash panel under the column or the shift lock actuator. You’ll want the panel off to remove the center console, and you’ve no need for the actuator.

Step 6: Remove the Automatic Shifter

To start, you’ll need to remove the center console. You can remove the shifter without removing the center console. It isn’t easy, but I did it. However, I wasn’t able to get the lower shifter seal installed without removing it. So, go ahead and remove the console now.

Because of the way my aftermarket stereo was installed, I first had to remove the head unit. I have read that you can pull the console by unplugging the radio from the harness after the console is loosened and pulled back slightly. Your mileage may vary.

There are two bolts, one on each side behind a pair of plastic covers on the sides of the back of the console, and two screws on each side of the front of the console. The two on the driver’s side should be easy to get to, and you can get to the other two by opening the glove box. You’ll also need to disconnect the trunk release, the cigarette lighter, and the power rear view mirror remote, if you have one. And you’ll need to remove the shifter console cover. You should now be able to remove the console.

Now you can get to taking the actual shifter out. Simply unbolt the shifter base, and unhook the shifter cable and the shift lock actuator cable. You can also pull the shift lock actuator assembly out from under the carpet as well.

Prepare to get greasy.

Part 2: Outside the Car

Step 7: Remove the AOD

While not the simplest thing to do, it’s not that difficult either. There are countless sites on the internet that cover removing the transmission, as well as most manuals and even many magazine articles. So I’m not going to go into detail here, just remove the transmission, torque converter, and flexplate.

The only thing I will mention is the transmission cooler lines. You’ll likely not be reusing them, so you could just cut them out to make it easy on yourself. I took a little more time and removed them so that they could be reused, as I’m going to try and sell most of these components bundled together as part of an AOD swap kit. For some reason, some people do want to swap an AOD into their car. Beats me.

Step 8: Swap Transmission Harnesses

Okay, so technically this is inside the car. In order to do this, you need to have the harness disconnected from the transmission. Its easy to do at this point, after you’ve removed the AOD, and before you’ve put the interior back together. This is one thing many people skip over, choosing to jumper the AOD harness and do without a functioning neutral safety switch. Finding a manual transmission harness is easy enough, and they are definitely easy to install. The transmission harness plugs in at the left kick panel and is routed under the carpet and goes through the driver’s side of the transmission tunnel. Just pull back the carpet, which should be very easy to do without the seats or center console installed, and unplug the AOD harness. At this point the harness should be completely disconnected, making it easy to also just pull the harness through the transmission tunnel from the passenger’s compartment. Plug in and route the T5 harness the same way you found the AOD harness.

Step 9: Install the T5

Again, this is a procedure that has been beaten to death elsewhere. Be sure to use new flywheel bolts, and it’s also a good time to replace the rear main seal. Install the T5 already (and flywheel, clutch, pilot bearing, throw-out bearing, and clutch fork).

One thing worth commenting on, is fitting the shifter through the hole in the transmission tunnel. Mine didn’t fit. The B&M shifter base is a little taller than the stock base, so it could very well be a combination of factory tolerances regarding engine and transmission mounting points, location of the hole, and what shifter base you use. Not to worry though, because it was easy to bend the thin metal for clearance.

Step 10: Clutch Cable, Transmission Harness, and Speedometer Gear

Installing the clutch cable isn’t very difficult, it just takes a little heft to feed it through the shifter fork. The transmission harness plugs right up, with one connection toward the top of the transmission, one on the side, and one at the speedometer cable. Straight plug and play. Be sure to get the appropriate speedo gear for your car’s gearing and for the specific transmission you’re using.

Step 11: Install Shifter & Lower Shifter Seal

There are some differences between transmission tunnels. I’m not sure if these differences are due to the year of chassis, or because of the type of transmission from the factory. The images with the black floor pan are from the 92 GT (factory AOD), and the white is an 88 coupe (factory T5). My guess is there are differences due to transmission type. The 92 GT has a much lower, rounded tunnel, while the 88 coupe has a taller, flatter section of tunnel.

These images also illustrate why a factory lower shifter seal wouldn’t work in my situation. First, you can see the shifter was designed to sit flat on the top of a manual tunnel, when compared to fitment on an automatic tunnel. You can bend the trim ring to fit the automatic tunnel, but then the factory rubber seal wasn’t high enough to clear my B&M shifter. My solution was easy, and very sanitary. I picked up a $20 generic boot from my local autoparts store. This worked beautifully. I could be used by itself, or allows plenty of room for a factory boot that attaches at the center console to slip over.

Step 12: Interior

You’re just about done. You can now put the interior back together (be sure to take the opportunity to vacuum the carpet before putting the seats back in) and enjoy.

Mad Props

Here are the resources I used for the swap: