should be clear.) A burnt smell or brown coloration of the fluid is a sign of overheated oil from extra heavy use or slipping bands or clutch packs. The unit should be sent to the shop for inspection for possible trouble.
Not all transmission fluids are the same. Before you add fluid, check the manufacturer's recommendations fast. The use of the wrong fluid will lead to early internal parts failure and costly overhaul.
Overfilling the transmission can result in fluid foaming and the fluid being driven out through the vent tube. The air that is trapped in the fluid is drawn into the hydraulic system by the pump and distributed to all parts of the transmission. This situation will cause air to be in place of oil and, in turn, cause slow application and burning of clutch plates and facings. Slippage occurs, heat results, and failure of the transmission follows.
Another possible, but remote, problem is water, indicated by the fluid having a "milky" appearance. A damaged fluid cooling tube in the radiator (automotive) or a damaged oil cooler (construction) could be the problem. The remedy is simple. Pressure test the suspected components and repair them as required. After reassembly, refill the transmission with fresh fluid.
Linkage and Band Adjustment. - The types of linkages found on an automatic transmission are gear shift selection and throttle kickdown. The system can be a cable or a series of rods and levers. Whichever the type, they do not normally present a problem, and preventive maintenance usually involves only a visual inspection and lubrication of the pivot points of linkages or the cable. Adjustment of these linkages should only be done according to manufacturer's specifications.
If an automatic transmission is being used in severe service, the manufacturer may suggest periodic band adjustment. Lockup bands are always adjusted to the manufacturer's specifications after an overhaul. Bands are adjusted by loosening the locknut and tightening down the adjusting screw to a specified value. Then the band adjusting screw is backed off a specified amount of turns and the locking nut is tightened down. Not all bands are adjustable. For example, the General Motors turbo Hydra-Matic Model 400 does not have a band adjustment. If the band is worn to the point where it cannot perform its function, you should replace it.
Fluid Replacement - The Naval Construction Force (NCF), the COMCBPAC/COMCBLANTINST 11200.1 series, recommends maintenance be performed according to the manufacturer's specifications. These recommendations vary considerably for different makes and models. When you change automatic transmission fluid, read the repair manual first.
Service intervals depend on the type of use the transmission receives. In the NCF, because of the operating environment, more than a few of our vehicles are subjected to severe service. Severe service includes the following: hot and dusty conditions, constant stop and go driving (taxi service), trailer towing, constant heavy hauling, and around the clock operations (contingency). Any CESE operating in these conditions should have its automatic transmission fluid and falter changed on a regular schedule, based on the manufacturer's specifications for severe service.
Draining the transmission can be done in three ways. By removing the drain plug, loosening the dip stick tube, or by removing the oil pan. Have the vehicle on level ground or on a lift and let the oil drain into a proper catchment device.
Oil drained from automatic transmissions contains heavy metals and is considered hazardous waste and should be disposed of according to local naval station instructions.
Once the oil is drained, remove the pan completely for cleaning. By paying close attention to any debris in the bottom of the pan, you may able be to detect a possible problem. The presence of a high number of metal particles could indicate serious internal problems. Clean the pan; set it aside. All automatic transmissions have a filter or a screen located in the oil pan. The screen is cleanable; the falter is a disposable type and should always be replaced when removed. These are retained in different ways: retaining screws, metal retaining clamps, or O rings made of neoprene. Clean a screen with solvent and use low pressure air to blow-dry it. Do not use rags to wipe a screen dry as it tends to leave lint behind that will be ingested into the transmission hydraulic system. Any screen with a hole in it or any screen that is abnormally hard to clean should be replaced.
Draining the oil from the oil pan of the transmission does not remove all of the oil: the process is completed by draining the oil from the torque converter. To do this, remove the torque converter cover and remove the drain plug if the converter is so equipped. (Most modernContinue Reading