BYD Destroyer 05 ECVT Assembly Oil Service and Dual Motor Controller Disassembly Guide

Fault Background

The Destroyer 05's front compartment houses a 136.8kg ECVT assembly: dual motor controller, drive motor, and front transaxle integrated into one unit, using BYD E-CVTF-1 special fluid for both forced and splash lubrication. Routine maintenance on this assembly is half "fluid" and half "parts"—fluid checks and changes have strict level standards and torque requirements, dual motor controller disassembly has a set of fixed bolts and a conductive rubber pad that must be discarded, and the assembly's pressure sensors, oil temperature sensor, and breather valve each have their own replacement specifications. This article organizes these maintenance points into a field guide.

Technical Parameters and Composition

• General assembly requirements: For locations with three or more bolts, tighten them alternately and evenly, then torque in diagonal sequence; if alignment is required, tighten and torque the alignment bolts first.
• Torque tolerance classes: Class A (±5%, bolt failure endangers life or major vehicle function) use a torque tool to pre-tighten to 80% of target value, then torque wrench to target value in the next step with full inspection; Class B (±10%) use a tightening tool to pre-tighten to 90% of target value, then torque wrench to target value in the next step.
• Leak check: During ECVT assembly operation and when stopped, and in hot running condition 5 minutes after stopping, inspect all connection points—no fluid or oil leakage is allowed.

Dual Motor Controller Service Disassembly

1. Following other system service manuals, disconnect the oil inlet/return lines, coolant hoses, low-voltage wiring harness, high-voltage wiring harness, power distribution box, and mount components around the ECVT assembly—ensure proper support and protection of the assembly to prevent it from falling after mount removal.
2. Remove the 8 internal hex bolts on the window covering the motor three-phase copper busbars on the controller.
3. Remove the 6 hex flange bolts for the motor controller three-phase copper busbars (installation torque 11±2N·m).
4. Remove the hex flange bolts on the 4 mounting feet of the controller (installation torque 50±3N·m).
5. Separate the controller—note the conductive rubber between the controller and the transmission; discard it after separation.
6. Reassemble in reverse order of disassembly: must replace the conductive rubber, and pay attention to the controller guide studs and controller wiring board alignment pins to avoid damage.

Fluid Inspection and Replacement

Fluid inspection:

1. Raise the vehicle and keep it level.
2. Remove the engine undercover.
3. Remove the inspection window plug and sealing gasket.
4. Check the fluid level through the inspection window—a slight overflow of fluid from the window is the correct level; if overfilled, allow excess to drain until correct; if low, check all assembly interfaces and plugs for leaks, and if no leaks, add specified fluid (BYD E-CVTF-1) through the fill port to the correct level.
5. Install a new inspection window plug and sealing gasket (tightening torque 50±3N·m).
6. Wipe off any residual fluid from the assembly.

Fluid replacement:

1. Raise the vehicle level and remove the engine undercover.
2. Remove the drain plug and sealing gasket.
3. Catch the fluid as it flows out in a stream; after it changes from stream to drips, wait about 5 minutes to ensure as much fluid drains as possible, reducing residual oil.
4. Install a new drain plug and sealing gasket (tightening torque 50±3N·m).
5. Remove the filter: first remove the filter lock bolt (tightening torque 6±1N·m), then remove the filter housing (bolt tightening torque 25±3N·m), and replace the O-ring and filter element on the housing.
6. Install a new BYD-specific filter assembly, and reassemble the filter body and lock bolt in reverse order.
7. Remove the fill plug and sealing gasket, and use a special tool to add the specified amount of fluid: 3.0±0.1L for fluid change, 3.6±0.1L for overhaul (BYD E-CVTF-1).
8. Check the fluid level using the inspection method, install the fill plug and sealing gasket (tightening torque 37±2N·m), wipe clean, and reinstall the engine undercover.

Used fluid and used filter elements must be collected and disposed of centrally; do not pour into drains or throw in trash. Always use BYD-specified fluid; using incorrect fluid may damage the ECVT assembly.

Sensor and Breather Valve Replacement

Safety Warnings

• This article is for technical reference only. ECVT assembly service must be performed by certified personnel following OEM specifications; readers unfamiliar with the procedure must not attempt it themselves.
• Before removing mounts, ensure the assembly is properly supported and protected to prevent it from falling and causing injury.
• The conductive rubber from the dual motor controller must be discarded after separation and replaced with a new one during assembly; pay attention to the guide studs and wiring board alignment pins to avoid damage.
• Fluid must be BYD E-CVTF-1 specified type; used fluid and filter elements must be collected for recycling; do not pollute the environment.
• Before inserting the drive shaft into the differential port spline and locking the circlip, use an oil seal tool or protective sleeve to prevent scratching the oil seal; remove the tool after assembly.

Maintenance Insights

The ECVT assembly service manual specifies the "fluid" rules down to the millimeter: slight overflow from the inspection window = correct level, stream to drips then wait 5 minutes = fully drained, three plug torques of 50±3/50±3/37±2N·m—the fluid system relies on these numbers to ensure lubrication and sealing. For the "parts" side, there's an easily overlooked detail: the conductive rubber under the dual motor controller is discarded after each removal and must be replaced during assembly; it serves as the equipotential and sealing element between the controller and transmission, and skipping it is like planting a landmine for noise or interference. Also remember two maintenance tips: the filter lock bolt is only 6±1N·m (too much torque will strip the threads), and always install the oil seal protective sleeve before reinstalling the drive shaft (a scratched oil seal will inevitably leak and require rework).

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【This article is for reference only】