What Causes Transmission Slippage?

[StValentina]

Transmission slippage can be caused by the following issues: 1. Hydraulic oil level is too low. 2. Hydraulic oil level is too high, causing excessive air bubbles when vigorously agitated by the planetary gear set during operation. 3. Excessive wear or burning of clutch or brake friction plates and brake bands. 4. Excessive wear of the oil pump or leakage in the main oil circuit, resulting in excessively low oil pressure. 5. Slippage of the one-way overrunning clutch. 6. Damage to the piston seal rings of the clutch or brake, causing oil leakage. 7. Damage to the piston seal rings of the shock absorber, causing oil leakage. Here are some related steps for diagnosis: 1. For automatic transmissions exhibiting slippage, first check the hydraulic oil level. If the oil level is too low or too high, adjust it to the normal level and recheck. If the automatic transmission does not slip after adjusting the oil level to normal, no further repair is needed. 2. Inspect the quality of the hydraulic oil. If the oil appears dark brown or has a burnt smell, it indicates that the clutch or brake friction plates or the brake itself are burnt, and the automatic transmission should be disassembled for repair. 3. Conduct a road test to determine if the automatic transmission is slipping and identify the affected gear and the severity of slippage. Place the control lever in different positions and move the car. If the engine speed suddenly increases when the automatic transmission shifts to a certain gear but the vehicle speed does not increase accordingly, that gear is slipping. The higher the engine speed, the more severe the slippage.

[FrankMarie]

Last time I drove long distance, I experienced transmission slippage which scared me into pulling over to check. This is mostly caused by worn clutch plates losing grip, just like how shoes slip when their treads wear out. If it's especially noticeable during cold starts, it could be due to aged and darkened transmission fluid causing insufficient lubrication - my friend's old Accord had this issue. Another possibility is a clogged pressure valve or a malfunctioning solenoid valve, where insufficient pressure prevents gear engagement. Oh, and if the RPM skyrockets during sudden acceleration without corresponding speed increase, it's likely the one-way clutch in the torque converter failing. All these situations require professional diagnosis with computer scanning to accurately identify the problem.

[OJasmine]

The mechanic often tells me that transmission slippage is 80% likely due to fluid issues. Over time, the oil accumulates metal shavings and impurities, which can clog the oil passages and affect transmission efficiency. Alternatively, aging oil seals may leak, causing insufficient hydraulic pressure, leading the clutch plates to generate heat through friction in a semi-engaged state. A rare but critical situation is a malfunction in the control module, where incorrect electrical signals to the clutch result in incomplete engagement. If the car has been undercarriage-dragged or involved in a collision, it's essential to first check if the transmission housing is deformed, potentially squeezing internal gears. It's recommended to change the transmission fluid every 60,000 kilometers to significantly reduce the likelihood of slippage.

[OIker]

Just took over the family's old car and encountered gear slippage. The 4S technician said three possible issues: clutch disc thickness below 1mm requires replacement; transmission filter clogged like coal briquettes hindering oil circulation; loose input shaft bearing causing gear misalignment. They also checked oil pressure with a diagnostic tool – normal idle should exceed 45psi. Special reminder: never use wrong transmission fluid type, incorrect viscosity is like feeding machines wrong medicine. After repair, I monitor fluid level and color during every maintenance – dark red with sour odor indicates replacement needed.