Diagnosis
A loud grinding noise when engaging the self-propel drive on your EGO LM2135SP indicates mechanical failure within the drive transmission. The sound is almost always caused by stripped plastic gears in the gear set or a damaged component in the self-propelled unit assembly. This is a common point of wear, especially if the mower has been used on steep inclines or with the drive engaged while starting or pulling the mower backward.
How to Fix It
You will need to inspect and likely replace the self-propelled drive components. Follow these steps:
- Disconnect the battery and tip the mower onto its side (with the air filter side up).
- Remove the rear wheel on the side where the drive unit is located to access the assembly.
- Inspect the visible gear set (Part #2826428002) for cracked housings or stripped teeth.
- Check the self-propelled unit (Part #2826067001) and motor & gear assembly (Part #2826577002) for damage. Spin the wheels by hand—grinding or binding confirms internal failure.
- Ensure all hexagon socket screws (Part #5620157006) securing the unit are tight, as loose screws can misalign gears.
If That Didn't Work
If the grinding persists after replacing the gears and drive unit, the issue is internal to the DC drive motor itself (Part #2730252001) inside the power unit. A failed motor bearing or internal commutator can also produce a grinding sound. This requires replacing the entire drive motor assembly, which is a more involved repair.
Heads Up
Do not continue to use the mower with a grinding drive. Operating it in this state will catastrophically destroy the plastic gear teeth and can damage the motor shaft, turning a simple gear replacement into a much more expensive motor assembly repair.