Super 10 for a 3:90 rear ends?

A double over just means that you have both .86 and .73 with the flip of a switch. With 3.90 rears, there isn’t a factory transmission that I’m aware of that’ll get you lower rpms. I know a guy that built a “hybrid” 18 speed that gives him triple overdrive but in 18th gear, it whines so bad, he never uses it. I suspect that someone but a “A” ratio rear section on an RTX14609 “B” ratio main box.

 

All of the aforementioned 10 speeds are 1.00 in 9th gear and > .78 in 10th. A 13 or 18 is just going to basically give you a “split” gear between 9th and 10th. Your problem is rear end gearing.

 

What would be the cost factor to swap gears in both rears?

And the speedo factor.

 

My Transmissions are all RTX with the C ratio. They are .73 Overdrive.

 

Do they still make them?

I know a guy that had a tri axle dump truck that was geared way low, like 5 something Rears. He put in a double overdrive 13-speed transmission.

One day he asked me to haul a load of stone for him. In that double Overdrive when I hit 80 miles an hour I slowed down.

Double overdrive is no joke.