Volvo Repair: 1994 850 Volvo/Non Turbo, volvo dealer, hydraulic problem

Question
My Volvo inconsistently fails to engage into 3rd and O/D, especially on inclines.  Recently had transmission filter and fluid changed by the Volvo Dealer.  While accelarating the RPMS always indicate fuel delivery but tranny isn't responding, the dealer claims he can't reproduce the problem after three trips to Dealer.  What other components could cause this?  Modulator or Governor?  Thanks..

- Will

Answer
this is an electronic transmission and there could be many problems that would cause this.it could be a hydraulic problem or an electrical one such as a bad solenoid,wiring problem control unit problem.the problm would need to be duplicated so it could be checked properly.more than likely it is an internal fault in the transmission and many parts inside are not available.