🟡 Subaru Forester CVT judder and hunting — fluid issue

The Subaru Lineartronic CVT in the Forester develops shudder and hunting between ratio changes when the CVT fluid degrades. The chain-type CVT is smooth when the fluid is fresh but develops these symptoms as the fluid ages beyond 40,000 km. Using genuine Subaru Lineartronic CVTF-II fluid and changing every 40,000 km prevents the issue. Never use generic CVT fluid or Nissan NS-3 in a Subaru Lineartronic — the chain design requires a different fluid formulation.