2021 Toyota Tacoma Power Train

The contact owns a 2021 Toyota Tacoma. The contact stated that while driving 10 MPH, after depressing the accelerator pedal and then attempting to depress the brake pedal to make a left turn, the vehicle failed to respond as intended. An independent mechanic was contacted. The contact pulled over into a church parking lot. No warning light was illuminated. The vehicle was taken to an independent mechanic to be diagnosed; however, the diagnostic result was unknown. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 47,000.

Transmission constantly seeking a gear usually 5th to 6th while using Cruize control. At times over-reving to near redline. End up having to manuall downshift to fourth back and fourt to drive. End up shifting more frequently that would if driving my mauual 6 speed transmission tacoma with the V6 as well.

1. What component or system failed or malfunctioned, and is it available for inspection upon request? The "coolant bypass hose/joint" (Part #: 16356-31051) located at the rear of the engine, connecting the two heads, failed. This part is made of plastic and is known to be a weak point in the 3.5L V6 (2GR-FKS) engine. The failed component is still in the vehicle and can be inspected upon request. 2. How was your safety or the safety of others put at risk? A coolant leak from this component can lead to engine overheating, which could cause sudden engine failure while driving, increasing the risk of an accident. Since the leak is not easily visible under the hood, a driver may not notice the issue until significant overheating occurs, potentially leaving them stranded in unsafe conditions. 3. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes, the issue was confirmed by the dealership after an inspection. They identified the coolant bypass hose/joint as the source of the leak. Many users on the forum TacomaWorld have also experienced the same issue with their vehicles. 4. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? The vehicle was inspected by the dealership, but it has not been inspected by Toyota directly, the police, or an insurance representative. 5. Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? There were no warning lamps or dashboard messages indicating a problem. The only symptom was a small puddle of coolant on the ground a week after purchasing the vehicle. Upon further inspection, a trail of coolant was observed running down onto the passenger side of the transmission bell housing. Would've costed me 1,000 dollars if didn't have warranty.

I was idling in line for food when I noticed my thermostat gauge going slightly higher in temp. All of a sudden I hear a loud hissing sound and smoke coming off of the engine as well as a chemical burn smell. I pulled over to the side in fear that a fire could potentially start. After some research I’ve concluded that it is the rear coolant bypass joint. It was a high stress situation where my family was in my vehicle. Please look into this!

Vehicle purchased less than year ago. Vehicle has approximately 10,000 miles on it. I am on my second rear differential replacement. The original and the first replacement were both making a whining noise. Dealer inspected and found metal shavings in both. There are numerous complaints of similar situation on Tacoma owner websites. A new vehicle that is less than a year old should not be on its 3rd rear differential. A failure of the rear differential at high speed or in congested traffic could have catastrophic consequences for occupants as well as any other nearby vehicles.

Visible oil leak or staining in rear differential is consistent with a prior recall in 2016-2016 model years as described in this document https://static.nhtsa.gov/odi/rcl/2017/RCAK-17V285-5030.pdf. This is a 2021 model year vehicle, purchased brand new in January 27, 2021, with less than 10,000 miles. This document indicates that "If the vehicle is operated with an insufficient amount of oil in the rear differential, the differential may seize and cause a loss of control, increasing the risk of a crash."