DECREASE OF POWER IN BASTER TRACTOR 9330

I have a 9330 Steiger tractor from the Case International, it is Power Shift, without loading the mechanical set works all its speeds in a normal way, when attached to the agricultural implement, for example a Big Rome of 30Discos, does not accept the 5 and 6 speed, has check the pressures of the EMBREAGUES Packages, injection pump, injectors, injector pump, injector pump, injector pump, injectors, injectors, injectors Injection, and I have not really found the fault, if someone has had experience with the topic, help me.