Causes of gearbox crunching when shifting automatic:
*Low transmission fluid: The fluid provides the lubrication and pressure needed for smooth gear shifting. Low fluid levels can cause increased friction and noise.
* Contaminated Transmission Fluid: Dirt, metal shavings, and debris in the fluid can clog the solenoids and valves, preventing the transmission from operating properly.
* Wearing transmission solenoids: The solenoids regulate the flow of fluid to the various clutches, allowing you to change gears. Worn or faulty solenoids can result in harsh gear changes.
* Wear on gearbox clutches: Clutches provide the clutch to change gears. Their wear can lead to slipping and crunching.
* Torque converter failure: The torque converter provides initial traction and torque between the engine and transmission. Its malfunction can lead to noise and crunching when changing gears.
* Bearing and Gear Wear: Over time, bearings and gears can wear out, causing noise and shifting problems.
* Malfunction of the electronic transmission control unit (TCU): The TCU controls the operation of the gearbox. If it malfunctions, it may cause incorrect gear shifting and noise.
Solution:
* Check the transmission fluid level and add it if necessary.
* Replace transmission fluid and filter if dirty.
* Test and replace faulty solenoids.
* Take the vehicle to a service center to check the condition of the clutches, torque converter, bearings and gears.
* If the trailer hitch is faulty, it will need to be reprogrammed or replaced.
Important: A crunching sound when shifting gears is a sign of a potentially serious problem. Don’t ignore it and seek professional help as soon as possible to prevent more costly repairs in the future.