Case 580E Loses Forward when hot

[crane]

hey, i recently burnt my forward disc in my 580e so i replaced them myself.it worked ok for about a week then i noticed that the shuttle began to slip a bit. yesterday about 5pm i loaded some aggregates and when i was ready to put up the machine it was barely moving have to rev in 2nd gear to get to my garage. i then drained the tans fluid and put in some new oil. it then began to move again but with a delay when i put it in forward or reverse. early this morning i tried loading some sand and it was pushing at about 70% of its potential. my guess is that the transmission oil is breaking down due to heat,i plan to use sae40 grade engine oil instead and see how it goes. by the way i change the bellevile spring and seals when i changed the disc. does anyone know the correct way to place the belleville spring because it has a concaved shape

 

[flatbed]

If my shuttle shift goes south I think I will use my shuttle as a core vis tearing it down. Surely the remanuf. once are okay and ready to work????