CarFix Answers

2016–2019 Toyota Tacoma: Transmission gear hunting or constant shifting

Likely causes, ranked

  1. Factory shift calibration on the 6-speed automatic (ECM update)Shop
  2. Fuel-economy shift logic (ECT Power or manual mode helps)$0–$0DIY
  3. Larger tires changing effective gearingShop

Real-owner fix counts will appear here as reports come in.

DIY or shop: See DIY or shop section

Parts to check

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Symptom: On hills, or at highway speed with cruise control on, the automatic keeps shifting back and forth between gears. It feels busy and slow to respond.

Likely causes

  1. Calibration. Toyota issued ECM updates for the 3.5L V6 automatic. Tacoma World owners report that uphill gear hunting mostly went away once the truck relearned. One owner said that took about 1,400 miles.
  2. Shift logic tuned for fuel economy. Many owners switch to ECT Power or shift manually on hills.
  3. Bigger tires shift the gearing. Recalibrating the speedometer and possibly regearing help.

Cost

The update is usually free if your VIN is covered, and cheap if it isn't.

DIY or shop?

  • DIY: driving habits (ECT Power, manual mode).
  • Dealer: the ECM update.

Useful steps

  1. Ask the dealer whether your truck has the latest calibration.
  2. After the update, give it a few hundred miles to relearn.
  3. If you've put on bigger tires, recalibrate the speedometer.

Vehicle focus: 2016–2019 Toyota Tacoma.

Safety / mechanic note

This is a drivability annoyance, not a safety defect. Get the differential leak recall done if it applies to your truck.

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Recalls & service bulletins

Recalls

  • 17V285000 2017-04-27 Oil may leak where the rear differential carrier joins the axle housing on certain 2016–2017 Tacomas. Details

Technical service bulletins

  • T-SB-0077-16 2016-11-15 2016 Tacoma 2GR/automatic: ECM calibration update for shift feel, including gear hunting. Details

NHTSA complaints: 135 keyword-matched complaints for Toyota Tacoma 2016–2019 (of 992 total complaints queried, NHTSA complaints API by model year, queried 2026-10-15).

Always check your VIN for open recalls at nhtsa.gov/recalls.

Sources

What actually fixed it?

Had this problem? Tell other owners what the real fix was. Reports are counted above; we never show made-up numbers.

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