Trans upgrade

[TruckJDM]

Can a Eaton 8LL be updated to a 13 I have a 2016 T880 KW dump truck but it's OTR

 

[Injun]

Probably not. You'd have to look at the serial number of the transmission. If it says 8CM.... or 9CM.... it can be. If it doesn't, you would have to modify your drive line and add a splitter. That gets expensive.

 

[Hammer166]

8LL and 13/18 share a common architecture, but you'd likely have to replace all the internal parts and the air control system. That's assuming the cases are machined the same.
You can get the part breakdowns from the Eaton site, just start comparing part numbers on bearings, shafts and gears to see what all would be different. You'd probably end up with as much money as a reman.