I installed an overdrive transmission in my 62 1/2 ton truck last year-worked fine for a while but now jumps out of third gear going up a slight hill while in OD. Adjusted shifting arms, tried heavier grear lube (140 wt), all to no avail. Now just attach a bunji cord ! Any suggestions? All gears are quiet and mileage is over 20 mpg with my 235 six so would like to salvage the trans without having to pull it. This a three on a tree setup with a switch used to engage OD. Merry Christmas from Texas!
