Making a 9speed OD

Why not just convert it to a 13 speed.

 

u dont need a 13 speed auxiliary all you need is a couple of valves and a different shift know but you will not make it an overdrive trans. your top gear will still be the same 13 just a little easier to drive on the hills that's about all

 

Are you talking about making it a double over,with high gear against the dash?
I don't think the newer trans can be flipped. It was the rt and rto that they did that to.

 

You have to have 4th and 5th swapped around. Have to pull the shafts out,have the gears press off and on. Better to take it to someone that knows what they're doing. Not exactly a diy project.

 

I have no idea what the cost would be. You'll have to call around and see. It should be cheaper than swapping rears.

 

062 is on tract. If you put a 13 spd box on the back of that will give you about 12% overdrive. If you swap the gears in the front of the main box that will give you about 18% OD. Do both for about 30% OD.
There are many different options, transmission models, and ratios which maybe indicated by only a letter like B. RT12609B = 22% OD.
This is all off the top of my head and only meant as an example. The point of my reply is to inform you of this and that if you over gear for your HP and torque you will be shifting all the time. That will defeat your fuel savings and wear you out.
There is a Eaton sight on line that will answer all of those ratio and road speed questions.
The 13 speeds worked really well on lower HP engines because you could shift about every 450 rpm and keep them in their best rpm range.
What engine do you have?