2017 Toyota Highlander engine problems

“Transmission failure after whining noise, taken to Toyota multiple times with no diagnosis. Today was informed the transmission is failing by another mechanic. 193,000 miles.”

“My 2017 Toyota Highlander, VIN [XXX], has just under 85,000 miles. I was notified at the dealership (Stevinson Toyota in Lakewood Colorado) who inspected the vehicle yesterday that the vehicle has developed a timing cover oil leak on the passenger side. After further research I learned this is caused by premature failure of the factory applied FIPG sealant at the timing cover’s T junction. This is well documented as a known, widespread defect in the V6 engine used across multiple Toyota and Lexus models between 2014 and 2019. This failure is not due to wear, neglect, or misuse. It is the result of a documented manufacturing flaw that requires full engine removal and carries an extremely high repair cost — a burden that should not fall on customers when the underlying cause is a defective sealant application at the time of manufacturing of the vehicle. I was quoted $5400. I am deeply concerned that Toyota has not issued a recall for this problem, despite its prevalence and the clear safety risks it presents. This leak is not merely a “durability issue.” It has legitimate and serious safety implications, including: •The potential for engine fire due to oil…”

“I had been shopping, as I attempted to increase speed, my car wouldn't respond. I smelled something burning and I switched lanes because I needed a safe place to stop. I turned onto [XXX] in Pembroke (I think) and still had no forward (or backward) movement. The lower gears (D5 & D4 ) DID NOT show on the dashboard indicator. I called my husband and he came to me. Then we called AAA and had the car towed to Chichester Car Care. They couldn't fix my car. I then had it towed from Chichester Car Care to McGovern Toyota in Bow. NH.”

“The contact owns a 2017 Toyota Highlander. The contact stated that when the vehicle was taken to a dealer for routine maintenance, the dealer informed the contact that the rear main seal was leaking and needed to be resealed. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 95,402.”

“I drive a 2017 Toyota Highlander and am having issues with the transmission. The issues and poor craftsmanship on the UA80 8-speed transmissions. Toyota offered Technical Service Bulletins T-SB-0160-18, T-SB-0008-21, and a limited Customer Support Program (CSP ZJC). But very few VINs were included and there are tons of Highlander owners with this transmission facing $10,000+ repair bills for what is supposed to be one of the most reliable cars and car brands on the planet. This is very wrong. Toyota has not stood by its customers and have not done right by owners. Toyota needs to recall the transmissions and offer a remedy at no cost to the customer. This needs to be done now. It's completely unacceptable. Thanks for what you do and for reading! Appreciate you guys very much.”

“Formal Complaint to NHTSA – Summary I am submitting this formal complaint regarding repeated mechanical and electrical failures involving my 2017 Toyota Highlander, purchased as a Toyota Gold-Certified vehicle with an extended Platinum Warranty. Despite strictly following Toyota’s maintenance guidelines and using only certified dealerships for all services, the vehicle has become inoperable multiple times, requiring five separate tows and resulting in repair costs exceeding $10,000. In June 2025, a Toyota dealership replaced the engine after diagnosing a warped head due to water pump failure. Following this, the vehicle began experiencing repeated charging system failures and electrical malfunctions. Multiple components—including the alternator, battery, and sensors—were replaced at another Toyota dealership based on ongoing issues, but the problems persisted. On September 2, 2025, a Toyota technician identified a missing ground wire nut as the likely root cause of these electrical failures. He confirmed the issue originated during the engine installation and that the unsecured ground caused system malfunctions. After repairs, the vehicle was again returned…”