cat 931 transmission problem

[350 cummins]

hoping someone can point me in the right direction, have a cat 931 loader sometimes when you start it, it works properly and the next time you start it the transmission won't drive (will move forward a little but no reverse) has anyone had this happen or know what might be wrong
thank you

[coxy]

I have almost the same thing in my 518 you can run it all day good if you shut it off leave it set a few min start it up try to go no go rev it up a few times then it will go with no trouble I don't know if there is a charge pump in a cat tranny but as long as it keep going im not fixing it    have you tried new filters

[350 cummins]

new filters, pump rebuilt, cleaned suction screen, o-ring on cover
no change with anything that we have done
not sure what to try next

[treeslayer2003]

does it have spring applied trans brake? could be a problem, my IH did that once but turned out to be a week charge pump. if it weren't for the brake holding i would not have known any thing was wrong.