9 Speed

I told a guy that once got told that's stupid you can't convert them your a idiot. I said sorry if the serial number ends in c it can be changed look it up.

 

If the serial number on the trans ends in C. The overdrive is on the tran. A 13speed shifter head and an air line ran from the trans to the shifter head. You have A 13 speed worth a look down under.

 

If you stay on the flat land (KS or NE) a nine speed will work just fine.

 

I have an RTX 9-speed that is in my garage as a spare, but I thought Eaton and told me that model you can't make into a 13-speed unfortunately.

Where I used to work years ago, that Fleet had mostly 10 speeds and some 9 speeds.

With those trucks anyway they were very similar in how they pulled and ran, although I did prefer the 10 speed.

 

Driven both 9-10-8LL

Give me a 9 or 8LL any day over a 10. I hate 10s. Lo gear on a 9 (not 1st) is way better taking off if your heavy compared to 1st on a 10

 

Advantage is its lighter weight, and cheaper to fix, or rebuild, and very durable.
Disadvantages is you only have 9.
Wore out ^^ has a good point, is it a direct drive, overdrive or a performance.
Would need to know what your putting it in and what your going to do with it for more input.

 

Most 9 speeds now days you could convert into a 13. I bought a Volvo recently on the drive home home stopped at a loves with freightliner across the street during my 10 I swapped it into a 13 fairly easy and under 100$

 

9 speed is plenty if you are only grossing 80k, had one in this old jewel. Anything more is just to compensate for drivers inadequacies

 

The convertibles are RTOC 16909 and 18909

 

With today's engines and the torque they produce, a 9 speed would do just fine. The big jumps do force you to come off hills slower than you could with a 13, though.
In the days when they were common, road speed was limited on company trucks by reducing the governor rpm, and it was easy to get hung up in the top of a gear when climbing, and not have enough oompf to pull the next one. And nothing sucked worse than having to climb a grade with the engine screaming and bouncing off the governor.