4 Key Signs Your Transmission Needs Repair

Feature 1: Gear shifting fails (“gear lock” or “unable to engage gear”)

Specific scenarios:

Manual transmission: Complete stalling when shifting into 1st gear or reverse, or inability to engage any gear;

Automatic Transmission: No response when shifting to Drive (D) or Reverse (R) after ignition (vehicle does not move), or gear selector stuck in Park (P) and cannot be moved (after ruling out parking brake or brake switch faults).

Risk: Failure to shift gears means loss of power control. If this occurs in the middle of the road, it can easily cause rear-end collisions. Contact roadside assistance immediately; do not force the operation.

Symptom 2: Frequent “Power Interruptions” During Driving

Manifestation: Sudden speed loss when accelerating, or jerky movement with fluctuating RPM during driving. Severe cases may result in engine stalling (rare in automatics; possible in manuals due to gear slippage).

Risk: Power interruption eliminates acceleration capability, increasing rear-end collision risk on highways or inclines, or causing rollback failure on slopes. Immediately pull over and seek repairs.

Feature 3: Transmission Fluid Leak + Abnormal Wear (Including Metal Debris)

Key Indicators:

- Transmission fluid stains on the ground (fluid appears red/brown, thinner than engine oil, with no noticeable viscosity) indicate a leak.

Metal particles are visible in the fluid (using a paper towel to absorb the fluid reveals fine silver particles), or the fluid has turned black with a burnt odor.

Risk: Fluid leakage causes insufficient transmission lubrication. Metal particles accelerate wear on gears and bearings. Continuing to drive may lead to transmission failure (significantly increasing repair costs).

Symptom 4: Abnormal Noise Accompanied by Body Vibration

Manifestation: During driving, not only are “clunking” or “humming” sounds present, but they are also accompanied by noticeable vibration in the steering wheel and vehicle body (especially during acceleration or gear shifts). The noise intensifies as driving time increases.

Cause: Typically severe gear wear (such as tooth surface spalling or gear deformation) or bearing damage causes “eccentric vibration” during power transmission. If left unrepaired, this may lead to complete gear fracture or even transmission housing rupture.