9 speed eaton vs 10 speed

I wonder if that 9 speed is easily convertible to a 13 speed

 

9 speeds aren’t bad, little differences between gears, maybe 400 rpm vs 300 or so, TMC used 9 speeds for years OTR.
It’s all in what you get used too.

 

It's .73od with the 3.25 rears

 

If it’s a convertible 9 speed it should be something like a .83 in 9, the od box (to make it a 13, is what gives the .73, I believe a straight 9 is .74 in the big hole

 

Ratio

Get the trans model number, check it against this Eaton Fuller link & you will know the ratios..
If it an RTOC, definitely get it. Then spend the few hundred bucks & convert it to a 13..

My 9 speed is .73 od. Most 10's in late models are FR direct drives, or FRO .74 od.. Top gear rpm should be slightly lower with the 9..

A 9sp is the easiest transmission on the planet to drive, & tough as nails. You will never even need the low hole pulling a box, & it's just an easy H pattern repeated low/high.. I'll take a 9 over a 10 every time..

 

Most the convertibles it's an under drive box that the air lines aren't hooked up. Should still have the .73od as a 9 or 13.. As a 13, 12th under drive split will be .86..

 

Rtloc-16909 is the convertible 9spd. Im currently having the conversion kit installed. You can call a Freightliner dealer with the vin and they can tell you what trans is in that truck.