RepairPal Certified shops can diagnose and repair your 2004 Toyota Tacoma. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Scan test transmission control module required .. Parts stores can't do it! .. AAMCO Transmissions used to do that for free .. Suggest good independent repair shop or better yet a transmission shop do the testing .. No use offering a guess as its too many possibilities!