2021 Toyota Tacoma Transmission Problems

While driving slowly at 10 MPH, you pressed the accelerator and then tried to brake for a left turn, but your truck didn't respond as expected. You pulled into a parking lot safely, and no warning lights appeared on your dashboard. An independent mechanic looked at it, but the diagnosis results weren't clear, and the vehicle wasn't repaired.

Your transmission hunts between gears (usually 5th and 6th) while cruise control is active, sometimes revving near redline before shifting. You have to manually downshift to 4th to regain control, and the transmission shifts more frequently than it would in your manual 6-speed V6 Tacoma. A transmission control module reprogramming or fluid service may be needed to resolve the hunting behavior.

The coolant bypass hose at the rear of your engine (a plastic part connecting the cylinder heads) can fail and leak coolant, causing your engine to overheat. You might notice a small puddle of coolant under your vehicle, but the leak may not be obvious under the hood, so you could suddenly experience engine overheating while driving without warning. A dealership inspection and repair would typically involve replacing the coolant bypass hose assembly with a new one.

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.

The truck will accelerate on its own during highway speeds of 60+ MPH and residential 25+ MPH. Also accelerates when coming up to a stop sign causing me to almost hit a child in a crosswalk. There was no cruise control engaged during the incidents. I took it into the Autonation toyota dealership twice and they said they could not reproduce and or duplicate the problem. It is very frightening when it happens as it lasts between 4-5 seconds if you do not apply the brakes hard. There has not been any warning lights or anything that comes up on the dash board.

I was my 2021 Toyota Tacoma home after work on the highway at night at 11:00 pm. While on the highways there was highway construction and traffic was coming to a stop. I was driving in the slow lane doing 60-65. As I approached the stopped traffic i let my foot of the accelerator pedal and put my foot on the brake pedal to slow down, as i did this the rpm's jumped up to 4000 and the truck went to take off full speed on its own. I held the brake pedal down to the floor and i shifted the truck from drive mode to sport mode than back to drive mode. ( I panicked) but soon as i did that the engine stopped accelerating thankfully because i had many stopped cars in front of me that i would have plowed into. I love my truck but I am not scared to drive it always have my hand on the shift waiting for it to happen again possibly.

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."

VEHICLE WILL NOT HOLD 6TH GEAR WHILE IN CRUISE CONTROL. VEHICLE WILL SUDDENLY DOWN SHIFT TO 5TH AND SOMETIMES 4TH. THIS MAKES THE VEHICLE SURGE FORWARD ABRUPTLY.

UPON ACCELERATION VEHICLE WILL HAVE DELAYED ENGAGEMENT, UP TO AND INCLUDING A NEAR STALL OR STUTTERING. HAS LED TO SEVERAL NEAR MISSES (X2). THE TSS SYSTEM TAKES OVER AND DOES IT'S THING VERSUS ALLOWING THE DRIVER TO DRIVE THE VEHICLE FOR THE CONDITIONS. EXAMPLE WOULD BE AUTOMATIC APPLICATION OF BRAKES DUE TO DEER IN ROAD CAUSING LOSS OF CONTROL ON AN ICY ROAD WAY. DRIVER RELEASED GAS PEDAL AND WAS COASTING AS DEER WAS CROSSING. DUE TO BRAKES BEING AUTOMATICALLY APPLIED, VEHICLE BEGAN TO SLIDE, DEER BECAME SPOOKED AND STOPPED CROSSING, VEHICLE ENDED UP PARTIALLY IN THE DITCH. AFTER MULTIPLE OCCURRENCES (5+ MEMORABLE), DRIVER HAS LOST ALL FAITH IN THE SAFETY AND RELIABILITY OF THIS VEHICLE AND DOES NOT TRANSPORT PASSENGERS AS THEY FEAR FOR THE PASSENGER'S SAFETY. DRIVER ONLY UTILIZES VEHICLE BECAUSE IT IS THEIR LAST AND ONLY MEANS OF TRANSPORT.