How to Replace a 4R55E With a 5R55E

by Adam Cloe Ph.D./M.D.

Many Ford Explorers come with a 4R55E four-speed automatic transmission. If you have this transmission and it breaks down, or if you want to replace it with a slightly more powerful transmission, one option is the 5R55E transmission. Because the connections for these two transmissions are the same, the 5R55E can be swapped for the 4R55E version, although this swap will cause the car to treat the five-speed 5R55E model as if it only has four speeds.

Removing the 4R55E

1

Jack up the front end of the Ford Explorer using the car jack. There are two important parts of doing this safely: the surface and where you put your jack. Avoid jacking the Ford Explorer on a slanted or uneven surface. Position the jack under a sturdy portion of the Explorer, such as the axle, and either put it on jack stands or use wheel chocks to hold your Explorer in place.

2

Clear a path to the starter motor. There are many pieces of equipment that will impede your access to the starter motor, such as the negative battery cable, the transmission throttle linkage, the oil filler tube, and the wiring connectors for the solenoid, starter motor, sensors and the backup switches. Disconnect all of these pieces to get access to the transmission.

3

Remove the starter motor. First you will need to remove the starter motor wiring and then unbolt and remove the starter motor.

4

Drain the transmission fluid.

5

Clear a path to the transmission. This means you will need to remove any tubes impeding your access to the exhaust pipe. Remove the exhaust pipe, then disconnect the speedometer cable and the shift linkage from the transmission. If the speedometer cable is still in your way, you can use a zipline to secure it out of the way. Unbolt the drive shaft and disconnect it from the transmission.

6

Place the transmission jack under the transmission.

7

Remove the transmission mount and crossmember. You will need to slightly lift the transmission to take pressure off the mount so you can unbolt and remove the mount. The mount should be removed before you unbolt and remove the transmission crossmember.

8

Lower the transmission and secure it to the transmission jack with the jack's chain.

9

Disconnect the transmission from the rest of the engine. First you will need to take off the engine flex plate and then remove all of the torque convertor bolts, rotating the drive shaft to ensure access to all of the bolts. Disconnect the mounting bolts that connect the transmission to the engine.

10

Remove the transmission. First pull the transmission back so that it is completely clear of the engine. Use your bungee cord or wire to secure the torque converter to the transmission and then pull the transmission back even further and remove it from the car.

11

Place the transmission and the torque converter into a pan and drain all the transmission fluid from the torque converter.

Installing the 5R55E

1

Uncouple the torque converter from the 4R55E and insert it into the 5R55E, rotating it so that it fits properly. To check the alignment, measure the distance between the torque converter edges with the edges of the transmission; if the distance between the edges is the same on both sides, the torque converter is aligned properly

2

Insert the 5R55E into the engine; the guide pins will help you align the transmission and the engine.

3

Connect the 5R55E with the engine. In essence, this involves reversing everything you did in steps 9 and 7 when removing the other transmission. Re-connect and tighten the torque converter bolts, tighten the mounting bolts that connect the transmission to the engine, and re-install the crossmember and the mounting rack.

4

Install the oil filler tube and reconnect the exhaust tube, the transmission cooler lines, the engine cover, the throttle and shift linkage, the speedometer cable, the driveshaft and any other lines that were previously connected to the 4R55E.

5

Fill the transmission with new transmission fluid.

6

Lower the vehicle and reconnect the negative battery lead. Start the vehicle and shift through gears to ensure the 5R55E is functioning properly.

Items you will need

About the Author

Adam Cloe has been published in various scientific journals, including the "Journal of Biochemistry." He is currently a pathology resident at the University of Chicago. Cloe holds a Bachelor of Arts in biochemistry from Boston University, a M.D. from the University of Chicago and a Ph.D. in pathology from the University of Chicago.