2020 Toyota Tacoma Transmission Shifting Problems: Hunting Gears

Drivers of the 2020 Toyota Tacoma often report a frustrating issue where the automatic transmission frequently shifts between gears, or "hunts" for the correct gear, especially at highway speeds. This behavior can manifest as constant upshifting and downshifting, hesitation to downshift when power is needed, or a general feeling that the transmission can't settle into a comfortable gear. This article will help you understand, diagnose, and address these common 2020 Toyota Tacoma transmission shifting problems.

What drivers notice on this 2020 Toyota Tacoma

The primary complaint for 2020 Toyota Tacoma owners experiencing this issue is a noticeable lack of confidence in the transmission's behavior. Instead of smooth, predictable shifts, the truck might feel like it's constantly searching, particularly when cruising on the highway or encountering slight inclines. This can lead to:

• Frequent gear changes: The transmission cycles rapidly between gears, often 5th and 6th, even on flat terrain.
• Hesitation to downshift: When you press the accelerator to pass or climb a hill, there's a noticeable delay before the transmission responds by downshifting.
• RPM fluctuations: The engine RPMs might fluctuate without a corresponding change in vehicle speed, indicating the transmission is engaging and disengaging gears unnecessarily.
• A feeling of being underpowered: The truck may feel like it's struggling to maintain speed or accelerate smoothly.

At a glance: difficulty, repair cost, and diagnostic workflow

• Difficulty Rating: 8/10 — Advanced
• Common Symptoms: Constant shifting: The most common sign is the transmission repeatedly shifting up and down, especially between 5th and ; Delayed downshifts: When you require more power (e.g., accelerating to pass or going uphill), the transmission takes an ; RPM surging: The engine RPMs may briefly surge or drop without a corresponding change in vehicle speed, indicating the t; Reduced fuel economy: The constant shifting and engine working harder can lead to a noticeable decrease in miles per gal
• Estimated Repair Cost: $350–$2,800 (parts + typical shop labor)
• OEM Tooling Required: Standard OBD-II scanner and hand tools

Diagnostic workflow:

1. Confirm the symptom on your 2020 Toyota TACOMA.
2. Scan for stored or pending codes with an OBD-II tool.
3. Inspect the most common causes in this guide (visual checks first).
4. Run verification tests before replacing parts.
5. Repair, clear codes, and verify on a test drive.

Browse the model repair hub and make hub for related guides.

What is different on this year and model

The 2020 Toyota Tacoma, part of the third generation (2016-present), features a 3.5L V6 engine paired with a 6-speed automatic transmission. This powertrain combination has been known for its unique shifting characteristics since its introduction. While some drivers describe the transmission as being "busy" or eager to downshift to keep the engine in its power band, excessive gear hunting or severe hesitation is not considered normal operation. Toyota has issued several software updates over the years to refine the transmission's shift logic and improve drivability, suggesting that some of these issues can be related to calibration rather than a hard part failure.

Symptoms and warning signs

Recognizing the specific symptoms is the first step in diagnosing 2020 Toyota Tacoma transmission shifting problems:

• Constant shifting: The most common sign is the transmission repeatedly shifting up and down, especially between 5th and 6th gear, on the highway or slight grades.
• Delayed downshifts: When you require more power (e.g., accelerating to pass or going uphill), the transmission takes an unusually long time to downshift, making the engine feel sluggish.
• RPM surging: The engine RPMs may briefly surge or drop without a corresponding change in vehicle speed, indicating the transmission is not holding a gear properly.
• Reduced fuel economy: The constant shifting and engine working harder can lead to a noticeable decrease in miles per gallon.
• Unusual noises: While less common, any new clunking, whining, or grinding sounds associated with shifts should be investigated immediately.
• Check Engine Light (CEL): In some cases, a related sensor issue or severe transmission fault could trigger the Check Engine Light.

How to verify and confirm the issue

To confirm that your 2020 Toyota Tacoma is indeed experiencing transmission hunting, perform these checks:

• Test Drive: Drive the vehicle under conditions where you typically notice the problem. Pay close attention to your speed, throttle input, and the tachometer. Try to replicate the issue on flat roads, slight inclines, and during acceleration.
• Observe RPM and Speed: Note if the RPMs are fluctuating significantly (e.g., 300-500 RPM changes) without a substantial change in vehicle speed, particularly at steady highway cruising speeds.
• Check Transmission Fluid: While the 2020 Tacoma has a "sealed for life" transmission, the fluid level and condition are critical. A low fluid level or contaminated fluid can cause shifting issues. This check typically requires specific tools and procedures, often best left to a professional, to ensure the fluid is at the correct temperature and level.
• OBD-II Scan Tool Diagnostics:
  • Scan for Codes: Use an OBD-II scanner to check for any pending, stored, or historical Diagnostic Trouble Codes (DTCs), even if the Check Engine Light isn't on. Look for codes related to the transmission (P07xx), engine performance (P03xx, P04xx), or sensor inputs (P01xx, P02xx).
  • Monitor Live Data: Connect the scanner during a test drive and monitor critical parameters like Transmission Fluid Temperature (TFT), engine RPM, vehicle speed, throttle position sensor (TPS) percentage, Mass Air Flow (MAF) sensor readings, and commanded gear vs. actual gear. Inconsistent readings from these sensors can directly impact shift logic.
• Research Technical Service Bulletins (TSBs): Check if Toyota has issued any TSBs specifically addressing transmission hunting or shifting concerns for the 2020 Tacoma. These often point to known issues and recommended fixes, such as software updates.

Common causes (most likely first)

Several factors can contribute to 2020 Toyota Tacoma transmission shifting problems:

• Transmission Control Module (TCM) Software/Calibration: This is a very common cause for newer vehicles. The original factory programming might not be optimal for all driving conditions, leading to excessive hunting. Toyota has released updates to address these issues.
• Low or Contaminated Transmission Fluid: Incorrect fluid levels or degraded fluid can prevent proper hydraulic pressure and lubrication, leading to poor shifting. Even a slightly low level can cause significant problems.
• Throttle Position Sensor (TPS) or Accelerator Pedal Position (APP) Sensor: If these sensors provide inaccurate input to the engine control module (ECM) or TCM, the computer won't know the driver's true power demand, leading to incorrect shift decisions.
• Mass Air Flow (MAF) Sensor: A dirty or faulty MAF sensor can send incorrect air intake data, affecting engine load calculations and subsequently the transmission's shift points.
• Oxygen (O2) Sensors: Malfunctioning O2 sensors can cause the engine to run too rich or too lean, impacting overall engine performance and confusing the transmission's shift logic.
• Torque Converter Clutch (TCC) Issues: If the torque converter clutch isn't engaging or disengaging properly, it can feel like the transmission is slipping or hunting for gears.
• Valve Body Solenoids: Sticky or failing solenoids within the transmission's valve body can prevent proper fluid flow, leading to delayed or harsh shifts.
• Internal Transmission Wear: While less common for a 2020 model, excessive wear on clutch packs or other internal components can eventually lead to shifting issues.

Related guides on this vehicle

• P0135 2001 Toyota 4Runner: O2 Sensor Heater Circuit Diagnosis
• 2022 Tacoma Transmission Shifts Too Much: Hunting Gears Fix
• Checking Transmission Fluid Level When Hot 2020 Toyota Rav4

Step-by-step diagnosis and fixes

Addressing 2020 Toyota Tacoma transmission shifting problems typically involves a systematic approach:

• 1. Check Transmission Fluid (Professional Recommended): Have a qualified technician check the transmission fluid level and condition. If it's low, top it off. If it's dark, burnt-smelling, or contains debris, a fluid and filter change may be necessary. Ensure the correct Toyota WS (World Standard) fluid is used.
• 2. Scan for DTCs and Live Data: Use your OBD-II scanner to re-check for codes and monitor live data during a test drive. Pay close attention to MAF, TPS, O2 sensor readings, and Transmission Fluid Temperature. Inconsistent or out-of-spec readings can point to a faulty sensor.
• 3. Check for TSBs and Software Updates: This is often a crucial step for newer vehicles. Contact a Toyota dealership or a shop with access to Toyota's service information to see if there are any applicable Technical Service Bulletins or software updates for your specific VIN that address transmission shifting issues. A reflash of the TCM can often resolve hunting gears.
• 4. Inspect Sensors and Wiring: Visually inspect the wiring harnesses and connectors for the MAF, TPS, and O2 sensors for any damage, corrosion, or loose connections. Clean the MAF sensor with specialized MAF cleaner if it appears dirty.
• 5. Test Drive and Monitor: If you have access to an advanced scanner, perform a test drive while monitoring the commanded gear vs. actual gear, as well as torque converter lock-up status. This can help pinpoint if the problem is in the command from the TCM or the mechanical execution within the transmission.
• 6. Advanced Diagnostics: If the above steps don't resolve the issue, further diagnosis of the valve body, solenoids, or torque converter may be required. This often necessitates specialized equipment and expertise. For more general diagnostic help, you can explore our All repair guides.

Repair options and cost factors

The cost to fix 2020 Toyota Tacoma transmission shifting problems varies widely depending on the underlying cause:

• Software Update/Recalibration: If a software update is available and resolves the issue, this is often the most cost-effective solution, typically costing $150-$300 at a dealership.
• Transmission Fluid Service: A drain and fill (not a full flush, which can sometimes exacerbate issues) can cost $200-$400, including fluid and labor.
• Sensor Replacement (MAF, TPS, O2): Replacing a faulty sensor can range from $150-$500 per sensor, depending on the part and labor involved.
• Valve Body Repair/Replacement: If solenoids or the valve body itself are at fault, repair or replacement can cost $800-$2,000.
• Torque Converter Replacement: Issues with the torque converter can lead to costs of $1,000-$2,500 or more, as it often requires transmission removal.
• Transmission Rebuild/Replacement: In severe cases of internal wear, a transmission rebuild or replacement could be necessary, costing anywhere from $2,500-$5,000+. This is less common for a 2020 model unless it has very high mileage or has been subjected to extreme conditions.

For more specific information on your vehicle, visit the Toyota Tacoma model hub.

When to see a professional

While some basic checks can be performed by a DIY owner, it's advisable to see a professional technician if:

• You lack the necessary tools (like an advanced scan tool) or experience to diagnose complex transmission issues.
• The Check Engine Light is illuminated, indicating a potentially serious underlying problem.
• Basic troubleshooting steps, such as checking fluid levels and cleaning sensors, do not resolve the issue.
• You suspect an internal transmission problem, as these require specialized knowledge and equipment.
• You need a software update or reflash for the transmission control module, which typically requires dealership-level tools.

Frequently asked questions

Is transmission hunting normal for a 2020 Toyota Tacoma?

While the 3rd generation Tacoma's 6-speed automatic transmission is known for its active shifting to optimize power and fuel economy, constant or excessive gear hunting, especially on flat ground or at steady speeds, is not considered normal. It often indicates an underlying problem that needs investigation, even if it's just a software calibration.

Can a software update fix 2020 Tacoma transmission shifting problems?

Yes, for many 2020 Toyota Tacoma models, transmission shifting problems like gear hunting can be resolved with a software update or reflash from the dealership. Toyota has released various calibrations to refine the transmission's behavior, improving shift logic and overall drivability, making this a common and effective first step.

How can I check my 2020 Tacoma's transmission fluid level?

Checking the transmission fluid level on a 2020 Toyota Tacoma's sealed automatic transmission requires specific tools and procedures, typically involving checking the overflow tube at a specific temperature range. It's not a simple dipstick check and is best performed by a qualified technician or a DIYer with the correct service manual and equipment to avoid damage.

Sources and further reading

For more general information on various automotive issues, you can browse our Browse vehicles section. If you're looking for details on specific diagnostic trouble codes, our Browse OBD-II codes page can provide valuable insights. You can also visit our Toyota vehicle hub for more information on Toyota models.

Disclaimer: This information is for educational purposes only and is not a substitute for OEM service procedures. Always consult a qualified technician for safety-critical work and specific vehicle repairs.