Ford’s Hybrid Transaxle, Part 1 - Transmission Digest

Ford’s Hybrid Transaxle, Part 1

Beginning with the 2005 model year Ford produced the Escape in a hybrid version (Figure 1) that was shared by the Mercury Mariner and Mazda Tribute, pretty much the same vehicle. The transaxle in these vehicles is called the eCVT, and even though there are no pulleys or a drive belt its ability to change gear ratios in a stepless fashion using electric motors puts it into the CVT category. The hybrid system in these vehicles is considered a series/parallel system, which means it can take off on electric power only or it can use the internal-combustion engine (ICE).

Ford’s Hybrid Transaxle, Part 1

Shift Pointers

Subject: Safety precautions for service or removal
Unit: eCVT transaxle
Vehicle Applications: Ford Escape, Mercury Mariner & Mazda Tribute hybrids
Essential Reading: Rebuilder, Diagnostician, R & R
Author: Pete Luban, ATSG

Shift Pointers

  • Subject: Safety precautions for service or removal
  • Unit: eCVT transaxle
  • Vehicle Applications: Ford Escape, Mercury Mariner & Mazda Tribute hybrids
  • Essential Reading: Rebuilder, Diagnostician, R & R
  • Author: Pete Luban, ATSG

Beginning with the 2005 model year Ford produced the Escape in a hybrid version (Figure 1) that was shared by the Mercury Mariner and Mazda Tribute, pretty much the same vehicle.

The transaxle in these vehicles is called the eCVT, and even though there are no pulleys or a drive belt its ability to change gear ratios in a stepless fashion using electric motors puts it into the CVT category. The hybrid system in these vehicles is considered a series/parallel system, which means it can take off on electric power only or it can use the internal-combustion engine (ICE).

Although you may not want to attempt any major repairs on this or any other hybrid vehicle, you can still service them safely and in relative ease. However, there is a caution associated with this: You have to know which plug is which. If you are expecting ATF to come out when you remove a plug but instead see anti-freeze, well – oops.

There is a plug on top of the unit right below the center electrical connector (Figure 2).

This is the inverter cooling-system bleed plug to purge the air as the system is being refilled through the coolant tank in the engine bay (Figure 3). The transaxle in these vehicles has a self-contained cooling system to keep the inverter at proper operating temperature; the coolant that runs through the transaxle is circulated by an electric pump.

You will have to remove the front splash guard to access the transaxle drain plug (Figure 4).

The check/fill plug is on the back of the unit (Figure 5), directly above the transaxle-mount bracket, which you may have to notch out to make accessibility easier the next time – no, not this time. The recommended fluid is Mercon® LV.

As with any hybrid vehicle, safety is of the utmost importance, which means before attempting any type of major repair work you should disconnect the hybrid system from the hybrid battery pack. On these vehicles this is done by accessing the rear cargo area and locating the battery-disconnect switch (Figure 6).

Even before attempting this the technician should be wearing class-zero rubber gloves rated to 1,000 volts (Figure 7). Notice that the rubber gloves have leather gloves over them to protect them from a puncture. Since electricity finds the point of least resistance, a pin hole in the rubber glove would make that point you, so check ’em before you use ’em.

You may be thinking, “How am I going to work on this car with all these gloves on?” You need to wear the gloves only until the hybrid-system voltage is verified low or none.

At this time the technician can safely approach the disconnect switch and rotate it from the “lock” position to the “unlock” position and then pull it out and reinstall it to the “shipping” position (Figure 8). The technician should now leave the vehicle alone for 60 seconds, which will allow the capacitors in the inverter to discharge. These capacitors are rated at 450 volts and 125 amps each, and there three of them in the inverter.

At this time the technician will verify that the high voltage has dissipated by locating the high-voltage checkpoints (Figure 9), which are marked with plus and minus signs, and will then check it with a Category III voltmeter rated at 1,000 volts to verify that the voltage has dissipated (Figure 10). Don’t assume; assumptions can be fatal. Remember, even when the system is discharged, the 330-volt battery pack is always lethal.

There are 1,000-volt-rated meters that have a Category II rating, but they may not protect you in the event of an errant electrical discharge, which can happen with high-voltage circuits.

You are now ready to remove the transaxle from the vehicle, but before you do you must disconnect the 12-volt battery to prevent the electric coolant-circulation pump (Figure 11) from running while the transaxle is being removed. Of course, the key should never be left in the ignition switch of any hybrid vehicle during repairs.

At this point what you see in Figure 12 is what you will have sitting on your bench.

In Part 2 of this series we are going to get into this transaxle and see what makes it tick.

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