I have a 77 IH transtar with a 13 speed road ranger. It has the A6913 style shift knob. The lo and high range shift portion works fine, but the OD split doesn’t work. There isn’t any air getting to the OD slave valve, I can get the valve to shift when I supply it with shop air. When the range lever is down I have air going in the S port and coming out the P port, air then comes out the green hose. When I shift to high range the air stops coming out of the green hose and the P port. This truck had the old style chrome top knob on it and has been switched to the A6913. Is this not a direct replacement knob? Thanks
Sounds like you have a deep reduction type of shifter, which is not compatible with your trans.
I was under the impression that the A-6913 was the latest model shift knob available for the 13 speed. Although this one doesn’t have a port labeled SP. Like I see in pictures of ones online. The port is there but isn’t labeled
Yeah I don't know I've just driven a bunch of trucks and deep reduction shifter don't let you grab deep reduction in high side and 13 speeds don't let you split in low side.
The splitter button won’t shift with the range lever in low. It has a mechanical lockout built into the lever.
The A-6913 is the correct valve for the 13 speed. Does the valve on A-6913 move only in high range but is locked in low range? There should be 2 supply lines on the valve. One should have air all the time the other should have air only in high range. There should be 5 threaded ports on the bottom of the A-6913 valve the marking can be difficult to see especially with the valve installed.
Yes the red splitter valve moves only in high range, it’s locked in low. There are 5 ports on the valve. I have air coming from a clear line all the time and air coming from a green line only with the selector in low range. When the selector is in high range there is only 1 air supply line. I have read somewhere about swapping the salve valve on the trans when switching from the chrome top knob to the A-6913. Is that what’s going on here maybe?
The air should come from a line when in high range not low range. Its been plumbed into the wrong line at the slave valve on the side of the transmission. Its the line marked H/L. Your transmission would have come with the A-4688 valve but may have been upgraded to the newer valve at some point. The slave valve is on the left side of the transmission at the top Its not the easiest place to work but you could plumb the H/L line into the air shift cylinder at the rear of the transmission, where the arrow is pointing on the lower picture.
I will have to look at what slave valve is on the trans and see where the lines are going. If I move it to the correct position on the slave valve would that solve the problem, or do you recommend moving it to the other location at the rear of the trans?
If you can move the line to the right location on the slave valve it should solve your problem. The valve is tough to get at on some trucks. That's why I suggested running a line to range cylinder.
Ok, I’m not at the truck at the moment. I’ll see how much room I have to work, I believe there is a plate that comes up in the floor maybe I can reach it from in the cab.
That was the problem, the green line was on the wrong side of the slave valve. I pulled the floor plate up and switched it through the floor.
That's good to hear. If you did not have access through the floor it would have been a real pain to get at the valve.
Definitely, thanks for the help.