A silent killer of automated transmissions or gearboxes is water or coolant mixing with automatic transmission fluid (ATF). This downside was once seen in older automobiles with uncared for engine cooling techniques, however is changing into frequent in later mannequin automobiles and trucks that have adopted their maintenance schedules. The result is at all times the identical: the transmission should be fully overhauled or replaced.
Can the Contaminated Fluid be Cleaned Out Earlier than Harm Occurs?
Nearly each automatic transmission on the highway in the present day uses cellulose based paper lined plates called clutches or frictions. These clutches act like brakes for shifting and stopping different parts inside the gearbox. When the shifter is placed into drive or reverse, it’s the frictions which can be being utilized.
The paper that lines the clutch plates is a really delicate material that’s glued to a steel backbone. Earlier than the paper is glued to the plate, it has the strength and consistency of a graham cracker. As soon as the material is bonded, it turns into a lot stronger and can final a really long time beneath normal working conditions.
The clutch materials is Hygroscopic. This implies when the clutches are uncovered to moisture, the paper material will displace ATF for water. That moisture reaches the steel plates inflicting rust, and breaks down the glue that bonds the paper to the plate. A research performed by International Lubricants Inc about the effects of water exposed to computerized transmission clutches states, “The testing indicated that water added at ranges as low as 600 mg/kg migrated to the floor of untreated paper frictionals and contributed to loss of the paper coating and erratic torque transfer properties.” In laymen’s phrases, that means lower than a tablespoon of water or engine coolant in a transmission could cause a failure.
How Did Water Get There?
There are 3 ways water can enter a transmission:
1. By way of the engine’s radiator. From the 1950’s to now, most automated gearboxes are cooled with the identical water primarily based system that retains the engine from overheating. There’s a separate tank within the radiator for transmission fluid that enables the coolant to take heat away from the ATF with out mixing the 2 liquids. When a leak happens between the ATF and engine coolant tanks in the radiator, the fluids will mix with one another. It was more widespread in older vehicles that had eroded cooling programs as a result of neglect, but some of at the moment’s newer vehicles are using supplies which can be failing because of stress problems in the cooling system.
2. Publicity to deep water. Driving through massive puddles throughout rain storms or off highway driving can expose the transmission’s respiratory system to moisture. The very best probability of preventing a failure is to verify for water within the ATF after a automobile has been in this sort of state of affairs.
3. Moisture entering through the dipstick. Most automobiles have a dipstick the place ATF is checked and added. Moisture can easily enter the transmission if the dipstick was sprayed with water throughout an engine cleansing, or in some instances, water draining from rain or a carwash drips onto the dipstick. GM and Chrysler have bulletins pertaining to this downside on some models of their vehicles. Certified shops may have entry to check for a lot of these bulletins. A tell tale sign of this drawback is moisture or rust across the dipstick tube.
Change or Rebuild?
It depends upon how much water blended with the transmission fluid, how lengthy the vehicle was pushed with the contaminated ATF, and the kind of gearbox your car has. Metallic and electronic components inside the transmission will rapidly corrode when exposed to moisture. If there is too much harm inside of the gearbox, the price of the components to rebuild the trans will exceed the cost of changing the unit with a remanufactured product. Some manufacturers like Nissan and Chevy have computers inside of the gearbox that will fail when exposed to moisture. These computer systems or mechtronics price as a lot as $2,000 and that doesn’t embrace rebuilding the rest of the unit. When elements value that much, it is typically a greater choice to exchange the gearbox fully.
To sum issues up, if water will get in a transmission, there is no option to get around an expensive restore. Flushing the fluid out will only price you further money and can make the inevitable failure occur sooner. Service the engine’s cooling system frequently and ask knowledgeable transmission mechanic in case your automotive is common for this kind of failure. If it is, bypass the radiator with an external oil cooler.