Mi auto cuando esta frío le entra la cuarta velocidad y cuando se calienta no cambia a la cuarta velocidad

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! If your ES300 only shifts into fourth when cold, it’s likely tied to the **transmission fluid temperature sensor** or a related issue with the cooling system. Since you replaced the radiator, double-check that the transmission cooler lines were reconnected properly and that there are no restrictions or leaks in the lines. Low or incorrect transmission fluid can also cause shifting problems. Make sure you’re using Toyota’s specified ATF (Type T-IV) and that the fluid level is correct. The transmission control module (TCM) relies on temperature data to determine shift points. If the fluid temp sensor is faulty or the fluid is overheating due to poor cooling, it could block fourth gear once warm. If this doesn’t fix it, scan for transmission-specific codes to dig deeper. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.