2017 Nissan Maxima Owner Questions Dealership Diagnosis as Transmission and Alternator Fail Within Four Weeks

A 2017 Nissan Maxima owner has taken to TikTok to expose recurring "limp mode" issues with his vehicle at just 77,000 miles, initially diagnosed as transmission and alternator problems. Following the dealership’s recommendation, he first replaced the valve body, but the issue persisted—within four weeks, the car broke down again and wouldn’t even start. The dealership then suggested replacing the entire transmission, offering to cover half the cost under Nissan’s “goodwill assistance” policy. However, he was recently informed that a faulty diode in the alternator had caused battery overvoltage and swelling, requiring an additional $1,600+ to replace the alternator, battery, and wiring harness. The owner questions why there were no prior warnings or diagnostic indications if such a serious electrical issue truly existed. He suspects the original “limp mode” incidents may have actually stemmed from an electrical system fault rather than transmission failure. He is now seeking a second opinion from an independent mechanic and expressing doubts about the dealership’s diagnostic expertise.