First check you fluid level, a low ATF quantity will cause slipping. And damage. Follow instructions in owners manual to learn how, if you don't know. If that's not it and the transmission has the proper amount of fluid, come on back here and we will try to find out what's going on.
after 80 to 160k miles the facings wear down,normal, needs a rebuild..just like a pair of shoes. most other cars never make it this far without some other part messing up.
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