Now we start getting into the fun part of the project. I’m not going to go into a lot of detail on the steps necessary to remove the AX15. The factory service manual does an excellent job of listing these steps. I’m just going to give a quick overview and list a few snags that I ran into.
- Remove the interior console and shift boot. Then unbolt the shifter housing from the top of the transmission
- Remove the front and rear drive shafts
- Remove the starter
- Support the motor and transmission using floor jack under oil pan
- Remove the cross member
- Unbolt the transmission mount
- Disconnect the transfer case linkage
- Disconnect the speedometer plug at the harness
- Remove the transfer case
- Support transmission using tranny jack. (I highly recommend that you borrow or buy one. I bought this one at Harbor Freight for $69.)
- Remove external clutch slave cylinder
- Unbolt dust shield bolts (Some of these are hard to see. If you don’t remove all of them you will find yourself cursing at the point you try to free the tranny from the engine.)
- Remove bell housing bolts.(The top 2 bolts require reverse torx sockets. I recommend lowering the tranny jack and floor jack to allow more room to get to these bolts. You can replace these with standard bolts if you like.)
- Remove the transmission. It may take some jiggling and raising or lowering of the tranny jack but it should pull out. (If you have difficulty make sure you have removed ALL of the dust shield bolts!)
- Roll the tranny out from under the Jeep.
- Unbolt the clutch and flywheel from the crankshaft.
Bolting in the AW4
Now we are really starting to get somewhere. Let’s walk through the steps necessary to bolt this baby in! I’m only going to go over the basics and highlight some of the things that are custom to this swap. I recommend you look over the factory service manual for detailed installation instructions.- Install the AW4 dust shields to the engine block. They will fit over the alignment pins. (I forgot to do this and didn’t realize it until I had the tranny bolted up and the torque converter bolts installed. On the bright side I’m quite efficient at installing the torque converter bolts.
- Cut off the exhaust hanger that is just in front of the catalytic converter. (The hanger interferes with the installation. This will save you a lot of trouble. You will have to weld in a new hanger when the project is complete. As you can see in the picture below I learned this hard way. Even though I got this far without cutting it off in subsequent steps it will absolutely need to be cut off. It’s a lot easier to do before the AW4 is bolted in.)
- Install the drive plate and spacer. Rotate it until the bolts line up. There is only one way to install this.
- Bolt the bell housing to the engine block.
- Install the 4 torque converter bolts. I would recommend that you line up your holes on the drive plate with those on the torque converter prior to lifting the AW4 into position. This will make it alot easier to find the first hole.
- Torque the bolts per the FSM.
- Install the CPS
Now you will want to bolt up the transfer case. Once that is complete you need to fabricate a plate for the tranny mount.
Brake Pedal
At this point we need to look at the shifter assembly and brake pedals. I started with removing the brake and clutch pedals. Boy this was a real pain! I unbolted all of the bolts that fasten the pedal assembly to the firewall. Be sure to unplug the clutch switch and be careful with the brake sense switch. From under the hood pull the master cylinder and clutch cylinders back. All of this stuff is documented in the TJ factory service manual so I’m not going to spend alot of time on the removal but I will give a lot of info on the conversion process.Here is a picture of the pedal assembly removed from my TJ. You can see the auto pedal that we are going to install.
Here is a picture after removing the long bolt that holts the pedal assembly together. It was interesting to find out that the pedal assembly was modular. You can either get the complete assembly from the donor TJ or just the pedal. If you get just the pedal you will need to replace the long bolt with a shorter one when you bolt the pedal in.
Here is a picture of the reassembled pedal.
And here is the finished product. You may find that the pedal does not contact the switch when the install is done causing the brake lights to stay lit. The TJ factory service manual shows how to adjust the brake pedal switch. I recommend that you look this up.
* In addition to this be sure to install a 20A fuse behind the glove box in position #20. This is the clutch interlock ignition bypass. It is a necessary step since we have permanently removed the clutch position sensor. Failure to do so will result in the Jeep not starting!
Cooler
It’s time to deal with the cooling issues. Here is a picture of the Flexalite cooler that I purchased. As you can see it has an integrated cooling fan.
Here in Arizona cooling a big problem in the summer months. When its 115 degrees out with the AC on max the radiator and condenser are at full capacity to keep things cool. I have already upgraded every single cooling system component including an electric pusher fan.
Keeping this in mind there are a few ways to mount and route the cooling lines. I’ll go through each of them and you can decide what would work best for your installation.
- Plumb the cooling lines into the radiator. My 3 core radiator can also be used as a tranny cooler. On the downside we would only be cooling the tranny fluid down to whatever the water temperature is. I have also read that this can add 20 degrees to the cooling system. In most climates this is probably ok. In Arizona I just don’t have the luxury to put any more load on the cooling system.
- Mount an auxiliary cooler in front of the radiator. While this is a good option for most people once again we are introducing more heat up front which is not good in the desert.
- Mount a remote auxiliary cooler. Now we are talking. We can cool the tranny fluid without introducing any more heat up front. This sounds like a good solution for the desert.
- Combine a front mounted cooler with a remote mounted cooler.
Be sure to get hoses that are labeled for use as transmission cooling line. Other rubber hoses cannot handle the high temperatures that they see. I used 1/4 NPT barbed fittings and 5/8″ hose clamps.
Where you mount it is your choice. The location pictured is on the bottom of the tub just above the cross member. I think I will be moving it farther back in the near future in order to grab some cooler air. (Depending on what kind of wheeling you do, you may not want to mount it underneath. Efficiency is lost if it gets covered in mud.) Like I said earlier, this is entirely up to you.
Getting ready to bolt up the cross member
We have test fitted the cross member while fabricating the tranny mount so we know it will fit. Before we bolt it in there is a couple things we need to do.
- Change the tranny filter
- Reinstall the oil pan
- Cut down the XJ cooler lines and install the 3/8″ compression fittings so they look like this:
- Screw the barbed fittings into the cooler lines then snap the cooler lines into the transmission
- Install the AX15 transfer case linkage bracket. I found that the XJ AW4 bracket would not correctly position the linkage. Use the TJ bracket and bolt it to the transfer case studs just like it was with the AX15.
- Modify the transfer case linkage. We need to drill the bracket that is bolted to the tub. I drilled new holes 1″ farther back on the bracket. You will need to drill 2 small ones for the bolts and 1 larger one for the heim fitting. Ideally I would recommend that these holes be drilled 1.5″ inches farther back. (I misplaced the picture that I took.)
- Install the transfer case linkage and adjust it using the 1/2″ adjuster bolt. Refer to FSM for more details.
- Install the shifter bracket and snap the shifter cable into position. Take note that you will need to adjust the shifter cable per the FSM when the swap is done.
- Remove the throttle body return spring and snap in the kick down cable that is attached to the AW4. It will look like this:
- Install the dipstick tube and dipstick.
- Now you can bolt up the cross member and install the transmission mount nuts.
Final Steps
We are now up to the final steps of the swap. Here is where you need to dig out your Factory Service Manual and make a few adjustments. I will outline these things and provide extra detail where necessary.
- Adjust the kick down cable
- Adjust the shifter cable
- Install the starter
- Install your front and rear driveshafts (Check the lengths carefully, you probably need to have the rear shortened and the front lengthened)
- Check rear pinion angle and adjust if necessary
- Adjust the brake sense switch located by the brake pedal
- Make sure your tranny harness is plugged in to the TCM, gray 8 way, and black 8 way plugs.
- Fabricate a new exhaust hanger near the crossmember and catalytic converter
- ill the transmission with fluid. I used 7.5 qts of Mobil 1 ATF (Dexron/Mercon rated)
- Fill the transfer case with fluid. I used 1.5 qts of Castrol ATF+3 (You need to use ATF+3!!!)
- I’m assuming you already routed and tied up the harnesses above the transmission and transfer case. This includes the transfer case and transmission breather lines. Be sure the breather lines are up on the firewall.
- Adjust the Park/Neutral (TRS) switch (If it will only start in Park and Neutral then skip this step)
