Difference in 13 speeds?

Torque rating 12 for 1250 ft/lbs and 15 for 1550 ft/lbs I believe

 

Along with what @magoo68 said. They shift differently. 12513’s cannot be pre selected for the splits when you upshift to another hole. You post select for up shifts.
Example. 7od to 8 dir. leave it in od go to 8 and then select to dir.
You pre select splits on down shift of holes.
Example. 8 dir to 7od. Select od than shift to 7 hole. Kinda hard to explain without showing you.
You do pre select for the range changes up and down as normal.
They also sing to you at about 60-65 mph in od. Not as bad as the 9513’s but they do have a whine.

 

They are a tough trans they put them behind the big power of the day. 475 cummins. 425 1693 and V8 Cats. And KTA cummins. There are still a lot of them running with millions of miles on them today.

 

I thought in that one I told ya how to do it.

 

This guy gets it. Exactly what i tried explaining recently about splitting my RTOO9513. And yes it whines like hell with a .62top gear. But the truck will do 80mph with 4.78 rear

 

What he said. That's how i shift our old .62 double. They get hot when you constantly lug em so don't do that. Im in love with it on 22.5 LP and 3.91/ 1600 is sweet spot on the 93. 75mph in last split and 65 in what most call direct (.73 on this one)

 

I wonder why on the 12513 transmission that you can pre-select the split when you downshift to a lower gear, but you can't pre-select the split when you shift into a higher gear.

I wonder why mechanically you can't do that.