Transmission question

[Mike L]

My service truck currently has a paccar px-8 (Cummins 8.3) and a 6 speed Eaton in it. If I wanted to swap in an 8LL or a 13 speed what model transmission would work? I’m thinking that some of the smaller dump trucks or tractors had to have one of these transmissions in them.

 

[Tyler d4c]

Rt/rto6610
Rt/rto6613 may also be a rtlo6613
There's a thread from a few months back about this subject talking about a f750 I may buy.

 

[Tyler d4c]

https://www.heavyequipmentforums.com/threads/transmission-swap.89272/

 

[Coaldust]

Consider the 8LL RTO-14908LL. That’s the unit I spec when I build new T370’s with the PX-9. Or, compare it to the RTO 8908LL price vs torque rating, oil cooler option, bla blah.

I like the 8LL and having three speeds in reverse for backing overloaded 2800 gallon tankers up steep driveways to make home heat deliveries. They really crawl.

The “ hidden” FWD gear is just a bonus. Lol.

 

[Don.S]

We have a little 10 wheeler with a 8.3 and a 8ll. On the job site its amazing and empty or half full its great to drive. Load it up with 15 or 16 ton and it starts to lack gears.

 

[Coaldust]

Good point. Interstate driving speeds and long grades might be an issue with only 8. My trucks with 8LL’s just cruise around villages.

 

[Don.S]

Looks like his truck it only a 6 wheeler so its probably not a big deal for power. I guess rear end ratio would make the biggest difference for him as to how fast it spins on the interstate. I can tell you that 2000rpm at 107kmh gets old fast.

 

[Mike L]

I’ve got 4.88 in the rear end and 73 mph ties it up right now. Truck is rated at 360 hp and 1000 ft lb of torque. I’ve got plenty of power and more torque than the transmission is rated for. I drive it easy
but I’m trying to think ahead should the transmission fail. Tyler I remember your thread but I was curious as to what would bolt up to my engine.

 

[Mike L]

Also I weigh about 27k so weight isn’t a huge issue. More or less looking for something with a low gear and will handle the engine torque. 6 speed is only rated for 850 ft lbs.