Transmission hunting between gears

Symptoms

• Frequent, repeated shifting between two adjacent gears
• Especially noticeable on hills or at steady cruising speed
• May be accompanied by a slight jerk with each shift
• Can happen with cruise control engaged or not

Likely causes

• CommonFaulty throttle position or speed sensorInconsistent sensor data can make the computer repeatedly reconsider which gear is appropriate.
• CommonTorque converter lockup clutch cycling on and offA converter that can't hold lockup steadily will cause the transmission to hunt for the right gear to compensate.
• PossibleEngine performance issue causing load fluctuationsAn engine misfire or vacuum leak can create load swings that make the transmission hunt to keep up.
• PossibleWorn valve body affecting shift stabilityGeneral wear can make gear selection less decisive.
• PossibleTowing or heavy load without an appropriate mode selectedSome vehicles hunt more under load if not switched to a tow/haul mode when available.

What to do

1. Check for a tow/haul or similar mode and use it if you're carrying a heavy load or towing.
2. Check the transmission fluid level and condition.
3. Get any check-engine light codes read, since engine performance issues can indirectly cause hunting.
4. Note if hunting happens more on hills, at steady speed, or under specific loads.
5. Avoid resting on cruise control on hilly terrain if hunting is frequent, since manual throttle input can sometimes reduce it temporarily.
6. Have a shop scan for both engine and transmission codes together, since the cause may be in either system.
7. Get the confirmed sensor, converter, or engine issue repaired rather than just tolerating the behavior.

Tools and parts

• OBD-II scanner

When to call a pro

See a mechanic to scan both engine and transmission systems together, since hunting can originate from either and needs a proper diagnostic.

Safety