Genuine Makita 227378-8 — Internal Gear 51 (51 mm). Precision internal (ring) gear designed for the impact-driver gearbox to restore smooth power transfer and correct engagement in the drive train.
This original Makita replacement is listed in official parts diagrams for Makita impact drivers such as the DTD152 and DTD153, and it also appears for some XDT-series impact drivers (for example XDT11/XDT13).
If your impact driver is grinding, slipping, or losing torque, replacing the worn internal gear with the 51 mm 227378-8 will bring the gearbox back to spec. Use this genuine Makita part together with other Makita parts when servicing the gear train to ensure proper fit and performance.
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