Eaton 13 Speed Grinding

Just bought an older dump truck with an Eaton 13 speed (the older one that splits the bottom into lo lo). Anyways when I bought it the lo lo didn’t work, it didn’t make any noise but just felt like a neutral, so just never used it and ran like a 10 speed. Trucks been fine for a while, but it has always ground some when the splitter went from low to high. Now today the truck started grinding while it was in high range and would feel like a neutral. If you put the truck in any of the high gears the transmission makes a nasty grind and doesn’t even try to grab. Just wondering what specifically to look for on the transmission before I pull it and put a reman in. What would cause this? Thanks!

 

Late reply, but synchros were shot. Had no clutch material left on them. This center gear between the 2 countershafts was also stripped internally and the bolts holding it on were loose. I just got it back together and it’s good as ever.

 

RT6613

 

Not holes for wire, but underneath was a little sheet metal piece with tabs that were supposed to be folded up, but it had broke so only half of it was on and then they walked loose