TM 9-2520-246-34 Section II. DESCRIPTION, OPERATION, AND DATA (MODEL 3053A) 3-4. General. The description and operation of the transmission model 3053A is very similar to that of transmission model 3052. Therefore, this section will refer to Section I, where applicable, to avoid repetition. Only the differences will be given in this section. 3-5. Description and Operation. a. Description. Figure 3-1 shows the transmission model 3053A used on the 2½-ton, 6x6, multifuel engine vehicles without front winch equipment. This transmission can also power a front winch by means of a power takeoff mounted on the left side of the transmission. (See fig. 3-2.) The construction of transmission model 3053A is almost identical to that of transmission model 3052, except for the fourth and fifth gear arrangements. This difference is shown by comparison between figures 3-13 and 3-6 and figures 3-14 and 3-8. b. Operation. (1) Power Flow. Power flow for transmission model 3053A is the exact opposite of the power flow for transmission model 3052. See figure 3-15 for the difference in power flow. See figure 3-12 for first-, second-, and third-speed power flow. (2) Fourth-Speed Power Flow. Power is transmitted from the input gear, which is coupled to the mainshaft by the fourth-fifth synchronizer, directly to the mainshaft. Because the interlocking action of the synchronizer in effect makes one continuous shaft of the input shaft and mainshaft, the drive here is direct; i.e., a 1-to-1 ratio. (See fig. 3-15, view A.) (3) Fifth-Speed (Overdrive) Power Flow. Power is transmitted by the countershaft fifth-speed (overdrive) gear to the mainshaft fifth-speed (overdrive) gear, which is coupled to the fourth-fifth (overdrive) synchronizer and to the mainshaft. (See fig. 3- 15, view B.) 3-6. Data. National stock number . . . . . . . . . . 2520-00-884-4833 Ordnance number . . . . . . . . . . . . . . . . . . . . . . 10872096 Make . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spicer Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3053A Type . . . . . . . . . . . . . . . . . . . . . . . . . . . Synchromesh Speeds: Forward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Gear types: Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Helical Mainshaft (except first-reverse) . . . . . . . . . Helical Mainshaft first-reverse . . . . . . . . . . . . . . . . . . . Spur Countershaft (except first) . . . . . . . . . . . . . . Helical Countershaft first . . . . . . . . . . . . . . . . . . . . . . . Spur Reverse idler . . . . . . . . . . . . . . . . . . . . . Spur-helical Bearings: Input shaft . . . . . . . . . . . . . . . . . . . . . . . Ball Mainshaft front . . . . . . . . . . . . . . . . . Straight roller Mainshaft rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ball Countershaft front . . . . . . . . . . . . . Straight Roller Countershaft rear . . . . . . . . . . . . . . . . . . . . . . . . Ball Reverse idler . . . . . . . . . . . . . . . . . . . Straight roller Input shaft size: Spline diameter . . . . . . . . . . . . . . . . . . . . . . 1.499 in. Number of splines . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Full length of splines . . . . . . . . . . . . . . . . . 2.375 in. Mainshaft (output end) size: Spline diameter l . . . . . . . . . . . . . . . . . . . . . 1.499 in. Number of splines . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Full length of splines . . . . . . . . . . . . . . . . .1.906 in. Gear ratios: First speed . . . . . . . . . . . . . . . . . . . . . . . . . . 5.02 to 1 Second speed . . . . . . . . . . . . . . . . . . . . . . . . 2.78 to 1 Third speed . . . . . . . . . . . . . . . . . . . . . . . . . 1.62 to 1 Fourth speed . . . . . . . . . . . . . . . . . . . . . 1.00 to l.00 Fifth speed (overdrive) . . . . . . . . . . . . . . . . 0.79 to 1 Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.90 to 1 3-9