Slipping gears are an indicator of wear on your transmission that will need to be inspected. If you notice that your car is having trouble changing gears, this may be a warning sign. If your car is running at excess rpm, or if you have excess ability to coast, it may indicate that your gears are not staying engaged while driving. This problem can occur with both manual and automatic transmissions. When you notice slipping gears, you need to be careful to not put further stress your already-damaged transmission.
Reduce the load on your car's transmission. Do not make sudden accelerations if driving an automatic-transmission car. If driving a manual-transmission car, avoid riding your clutch, sporadically hitting the accelerator, or starting on excessive inclines.
Notice when and under what circumstances your gears are slipping.
Listen for any unusual noises coming from your transmission. Document the type of noise and how often you hear unusual noises.
Contact or visit a repair shop. Describe the problem and what, if any, unusual sounds are coming from the transmission. A mechanic may ride with you or test-drive the car to help diagnose the problem.
If driving a car with a manual-transmission, avoid letting inexperienced drivers drive your car until the problem is fixed. Misuse of the clutch may cause more damage to your transmission. Avoid flushing the transmission fluid as a precautionary measure. Your transmission fluid may have thickened and it may contain shavings from wear that may be essential for whatever grip the transmission still has.