77 IH Transtar with a RTO 9513 no OD

There should be 4 or possibly 5 small air lines going to the valve on the shifter, 2 are supply lines. One supply line has air pressure all the time and the other has air pressure when in high range. One line controls the slave valve on the side of the transmission and another controls the splitter. If there is a fifth line it will be an exhaust for the shifter valve that exhaust below the floor. The line that has pressure in high range supplies the splitter control valve on the shifter its marked H/L in the diagram the valve should have the same marking where the line connects.


There was an update to the splitter shift collar and fork in the early 1980's. If the transmission still has the original splitter shift collar and fork you have to shift it properly or the fork and collar will wear out very fast. Fuller said: Do NOT PRE-SELECT when shifting the splitter. In other words when the splitter shift valve is shifted the shift needs to take place immediately not a second or two later when you release the throttle. I'm hoping someone here will chime in and maybe better explain hot to shift the splitter.

 

The old transmissions used different logic on the air system, as there weren't high range interlocks on the splitter. So on those old ones, there was air to both switches on the shifter, all the time. On the new shift knobs, the splitter switch doesn't get air until the range shift has actually occurred.

Maybe this thread will help?

"Roadranger Thirteen Speed Knob Questions" Roadranger Thirteen Speed Knob Questions