Shimano talica 8 2 speed

[Tunajuan]

Shimano talica are the best I've had mine for years it's time for me to learn how to clean and replace parts that are damage. Does anyone know what parts need to be change when the crank is slipping. Drag and everything else works fine. Thanks in advance

[Kev]

Can you be a little more clear on how it is slipping? As in the handle spins backwards?