Standard ratio for your 49 3/4-ton rear is 4.57 with an optional 5.14, same as 1-ton. Most were 4.57. Does it have a 3-speed or 4-speed? Not likely that a 3-speed truck would have the steeper ratio rear. Original 49 would have a closed (torque tube) front drive shaft to a carrier bearing with open rear shaft. 2 u-joints visible as the front joint is enclosed in the ball-and-socket on end of transmission. 3/4-tons were like that thru 53. 1-tons had all open u-joints. I guess your sure it's a 3/4-ton? 3600? pickup bed 7 1/2' long? It may have had a 54 or later transmission/ drive shaft swap already.

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