Family project truck, needing feed back

It was so long ago I couldn't tell ya if it was an rt or an RTLO. Came out of a 77 cabover kw if that helps. However, it operated just like the 15 in my 93 w9. The top two gears are backwards in the shift pattern. Are all 15s like that? Those are the only two I've ever had.

 

They got away from the top two turned around with the x plate. Being that old is was gonna be an RT with most likely square cut gears and nontapered bearings they made a lot of friction for sure and gear whine

 

If it was a double over it was probably a 13 spd regardless of the tag on the case. When you get into those taller gears it takes a lot of guts to pull it out and you can't hardly find a place to let one roll anymore.
It may have been what I have heard referred to as a frankin trans. As an example if you had a RTO12609B (22% OD) and put a 13spd back box on it (12% OD) you are 34% OD). Just sharing the idea and the figures are off the top of my head. Since her final drive is the same with more power that truck might have an advantage with larger od tires, LP 22.5 to 11 R 22.5 or to 11 R 24.5. You were probably just a bit over geared for your 11.1.

 

Im certain it was a 15. Got the same kind of tranny in my w9. 5 stupid low gears, flip the switch, go through five more, flip another switch and five more. With the top two in opposite positions of where you would expect them. In the KW with a kitty cat I only ever used those bottom 5 when pulling out of a hole. In the Pete with the tiny green engine you had to start on the bottom unless you was bobtail. Both had 3.55s for rears. 11rs on the Pete 24rs on the KW.

I'm thinking it was what wore out said. Different style gears and bearings making more friction. That 12 cylinder it was originally bolted to certainly made a lot more power than the 11.1

 

Just got back from take my Dad out to dinner. Was out of town on Fathers Day . At 81 , time is limited. Going with him tomorrow to see Mom at the home. Make the most you can out of each day.

 

[QUOTE="AshtonMarie81, post: 5250718, member: 179988".... currently this m11 with the super 10 cruises at 68mph between 1500 and 1600... it just lacks the pulling power for the northeast region... ... truck has 3.73 rears..[/QUOTE]
fwiw I pull 80,000 in the northeast with a '98 T800 and a 13 behind an M11 and lo pro 22.5's 4.55 rear gear and she needs it. I couldn't imagine 3.73 and a super 10.

 

My chart shows that both the RTLO 16918 A and B both have .86 and .73 overdrive. The RTLO 16618 has just the .85 overdrive.

Either way it should work well, except with 3.73 rears, tall 22.5, and .85 overdrive I think you will be in the 1700 RPM range @ 65 mph. I didn't catch what size tires you have though, but with tall 24.5's you would be slightly above 1600 RPM @ 65.