GM-GMC: 1992 chevy G30 van transmision not shifting properly, gm automatic transmissions, chevy g30

Question
automatic trans not shifting up or down.Is that caused by dirty filter.1992 chevy G30 automatic overdrive

Answer
A dirty transmission filter may cause a no shift problem.

But you will be lucky if that is all that it is.  After 1990, GM automatic transmissions became electronically controlled.  There could be a problem with the electronics or an internal problem with the transmission.

Take your vehicle to a reputable transmission shop for diagnosis.