Finally found an Auxiliary Transmission for my 51 1-ton GMC The tag is missing. I was hoping someone could identify the tranny and help me figure out the ratios.
The Box weighs about 100 lbs. Looks like it holds about 4 pints of oil. Front and rear gears are beveled, center set are spur. The stamped date show in the pic is 1967.
Fiddling with the linkage and spinning the yokes I came up with a .79 over, a neutral, a 1:1 and a 1.26 under. Then I had to pull the cover to confuse matters. Towards the front of the box a 19 tooth gear on the upper shaft meshed with a 24 on the lower shaft. (.791:1) Then middle set was 24 teeth upper and lower. The back set was 17 upper and 26 lower which works out to .653 or 1.53. I can't figure out how I get a 1.26 underdrive when I spin the yokes, unless it is a four speed with a 1.52 under and a 1.26 under and a .79 over.
Please splain it to me.
I have posted a picture at
http://oldgmctrucks.infopop.cc/eve/ubb.x?a=tpc&s=272004236&f=633004236&m=829109747 but have not gotten any replies.
Thanks for your help
Sidehill
