That looks a lot like my 57 2 ton, that operates the drum assembly on the rear of my transmission. My linkage is missing that goes from the lever to the drum.

57 GMC LCF 370
55 John Deere 40-W
59 John Deere 430-W
2000 GMC 4x4
56 John Deere 420-W
Pix on Photobucket