TM 9-2520-246-34 Section III. GENERAL MAINTENANCE 2-7. General. Because the transmissions, transfers, and power takeoffs are very similar in construction and material, use generalized cleaning practices, as recommended. If and when special cleaning practices are required, refer to the specific cleaning instructions in the pertinent chapter. 2-8. Cleaning. a. Cleanliness. Cleanliness of personnel, tools, and area surroundings is not only good practice, but it is a fundamental requirement when mechanical repairs are performed. This is particularly true of the areas in which transmissions, transfers, and power takeoffs are repaired or rebuilt. All of the information and instructions contained in this manual are given with the assumption that these conditions prevail in the working area. Transmission, transfer, and power takeoff repairs, except those of an emergency nature, should never be accomplished under any other conditions. b. Precautions. (1) Do not use drycleaning solvent, type II, (SD-2) Fed Spec P-D-680, near an open flame because it is flammable. Fire extinguishers must be provided when this material is used. Avoid contact of these solvents with the skin as they may cause cracks, mild irritation or inflammation of the skin. (2) Avoid contact of drycleaning solvent or lubricants with rubber parts since these materials can cause deterioration. (3) The use of gasoline, mineral spirits paint thinner, or benzine for cleaning is strictly prohibited. c. Cleaning Transmission, Transfer, and Power Takeoff Assemblies Prior to Disassembly. (1) Scrape or brush all accumulations of dirt or road mud from the transmission case and attached parts with a scraper or wire brush. Note and mark, by scratching the case with a sharp-pointed tool, any moist oil spots or unusually heavy accumulations of oil-soaked road mud, for these are good clues to the location of small cracks or holes that might escape notice in a visual inspection. However, do not confuse these accumulations with those that result from leaking gaskets or oil seals. A leak at a seal or a gasket is more or less normal for an assembly that has been in service for any length of time, and the area covered is generally localized around the shaft bores, power takeoff openings, etc. (2) Complete external cleaning with steam- cleaning equipment, or by hand brushing, using drycleaning solvent, type II (SD-2), Fed Spec P-D- 680, as a cleaning agent. Total immersion in a dip tank is also approved, provided the cleaning agent is drycleaning solvent. The use of stronger cleaning agents, such as caustic soda or detergents, is prohibited because of the corrosive effect on bearings. d. Cleaning Component Parts After Disassembly. (1) It is essential that the equipment used during the cleaning operation suit the particular cleaning job being performed. Round brushes should be used for internal bores, and square or rectangular brushes should be used for flat or external surfaces. Each part should be cleaned thoroughly and individually. NOTE Bearings require special handling. Cleaning, inspection, and preparation for use of ball and roller bearings are covered in TM 9- 214. (2) Clean all other parts of hardened oil, lacquer deposits, and dirt, paying particular attention to the small oil holes in the gears and to the lock ball bores in the shifter shaft cover. Remove all gaskets or parts of gaskets from surfaces, using a putty knife or other suitable scraper. Be careful to avoid scratching or gouging the surface metal. (3) Rinse the parts in clean drycleaning solvent type II (SD-2), Fed Spec P-D-680. This is a highly important operation. Spraying solvent over the parts or suspending the part in a mechanically agitated bath of solvent are the preferred methods of rinsing. In the absence of such facilities, however, the parts may be rinsed by immersing them in a container of clean drycleaning solvent and shaking them vigorously. Dry the parts with compressed air. 2-9. Inspection. a. General. (1) This section contains general inspection procedures for transmissions, transfers, and power takeoffs. Not all inspection procedures will apply to each assembly. Therefore, it will be up to maintenance personnel to apply the pertinent procedure to the assembly which they are inspecting. Most inspection procedures will apply to all assemblies. Special inspection procedures for an assembly are given in the respective chapter for that assembly. (2) All parts must be thoroughly examined and 2-15