Most Brownies have a data tag, usually on a side, early ones were brass, later ones are steel. Numbers on tag represent ENGINE torque rating, I e 5531 can handle engine torque of 500 ft. lbs.
OD position is fwd, right. Google for ratios. Very simple design, output shaft might not have seal, reverse threads to keep oil in. No parts are available. If Tru-Stop disc brake attached, a bonus. Lube shifter ‘til rails are free, make new shift rods from water pipe or EMT.

Send picture when can.

Must have 20” wheels, if front cast hub threads in, 1.5 ton truck, if stamped metal, 2 ton truck.

Ed

Last edited by EdPruss; 05/05/2022 2:29 AM.
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.