CAT 416B trans trouble

I have CAT 1994 416B goes in gear sometimes and most times not I have disconnected the netural solenoid makes no difference I would raise the rear on the machine and it would go in to gear some times but will not fluid is full and now nothing Removed the trans filter and started the motor and no fluid came out I think my trans pump is bad the machine has 6200 hours no debris in the pick up screen is time to pull it out? Any and all help would be great Thanks John