ASE G1 Auto Maintenance and Light RepairAutomatic Transmission/TransaxleMedium
A customer reports that their vehicle's automatic transmission sometimes 'clunks' into gear when shifting from Park to Reverse or Drive, but shifts smoothly once moving. What is the most likely cause of this complaint?
- AWorn or damaged engine/transmission mounts.
- BA faulty torque converter clutch solenoid.
- CA clogged transmission fluid filter.
- DLow transmission fluid level.
Show answer & explanationAnswer & explanation
Correct answer: A. Worn or damaged engine/transmission mounts.
A 'clunk' when shifting from Park to Reverse or Drive, without issues once moving, often points to worn or damaged engine and transmission mounts. These mounts are designed to absorb shock and noise; when they fail, the movement of the drivetrain during initial engagement can cause a noticeable clunk.
Why the other options are wrong
- B. A faulty torque converter clutch solenoid typically causes shuddering or harsh engagement once the vehicle is moving and the clutch locks up, not during initial P-R/D engagement.
- C. A clogged filter typically causes slipping or delayed engagement, not a 'clunk' on initial gear selection.
- D. Low fluid usually leads to delayed engagement, slipping, or harsh shifts across all gears, not just an initial clunk.
Drivetrain Mounts & Clunking
Worn or damaged engine or transmission mounts can cause a 'clunk' or jolt when shifting an automatic transmission from Park to Drive or Reverse due to excessive drivetrain movement.
- Mounts absorb drivetrain shock and vibration.
- Failure allows engine/transmission to move excessively.
- Often noticeable during initial gear engagement.
Memory trick: Clunk on engagement? Check the mounts, they're the shock absorbers.