Kyosho VZW020-01 Differential Case Seal 4pcs

A set of four differential case seals for Kyosho's VZW020 aluminum hard differential case.

The seal is the only thing keeping silicone diff oil inside the case. When it hardens, tears or gets pinched during assembly, oil weeps out past the case joint and the diff progressively loses the viscosity you set it up with. That failure is gradual and easy to misread: the car starts diffing out more in corners and losing drive on power, and it feels like a setup problem rather than a leak. By the time you see oil on the outside of the case, it has been running under-filled for a while.

Because the seal is compressed and permanently deformed the moment the case is torqued together, it should be replaced every time the diff is opened rather than reused.

Four are supplied, enough for a full service with spares. Note these are the service seals for the optional VZW020 aluminum case specifically, so that case needs to be fitted already. Kyosho lists the parent case as an option part for the V-One S II and S III.