When a corporate family sings the relocation blues

''When you move, you better have a good marriage, because everything else falls away - you have no support system.'' The comment is from author Judith Greber, who is discussing her second novel, ''The Silent Partner,'' and the problems families, especially corporate families , encounter today.

Like her book's main character, Molly, she is a mother and has moved several times because of her husband's career. Her experiences inspired her to write about the system many large corporations use of routinely moving employees around the country in order to provide them with experience and to fill executive positions within the corporation. From her own experiences, as well as those of friends, Mrs. Greber has concluded that this system is very damaging to families.

She notes that success in climbing the corporate ladder does not always bring happiness. And when combined with continual uprooting and relocations, which take a lot out of all family members, the results are high statistics for divorce, teen-age suicide, alcoholism, and drug use.

At one point she considered writing a non-fiction book about corporate families but decided instead to deal with their problems in a novel.

''The Silent Partner'' (New York: Crown Publishers Inc., 295 pp. $13.95) is an entertaining, touching, funny, sad, thought-provoking, and ultimately positive portrait of a family and a marriage in crisis. And, as an added bonus, the likable, sympathetic char-acters seem to be real people.

Clay and Molly Michaels, their three children, and Molly's elderly mother are coping with the usual problems of youth, middle age, and old age. These problems are compounded by the demands of Clay's employer. In fact, the family is about to be relocated for the eighth time in an 18-year marriage.

When they had moved to Los Angeles, the corporate headquarters, a few years earlier, Molly had thought her moving days were over. As she had done many times before, she transformed their new house into an attractive, comfortable home. She learned her way around Los Angeles. Her children settled into new schools and made new friends. Clay seemed to be satisfied with his new job. Molly put down her own roots by opening a gourmet food shop with two friends.

When Clay abruptly announces that he is being transferred to a corporate subsidiary in Philadelphia, Molly's world is turned upside down.

Not that her world isn't already troubled. She and her husband have stopped communicating. Clay's best friend has been fired, fueling Clay's fears that he, too, is expendable. Her mother, Thea, who has arrived for an extended visit, is showing some alarming signs of old age. Her teen-ager, Joanna, is critical and withdrawn. Molly herself is torn between her desire to be a perfect wife and mother and to devote herself to her business. And perhaps most upsetting of all, as she approaches her 40th birthday, is the fact that ''the lady in the mirror'' no longer matches her mental image of herself.

When the family moves to Philadelphia, all these problems seem to intensify at first. Gradually everyone except Molly adjusts and settles down. Molly still resents the move and the need to leave her business behind. She blames Clay for her problems. She considers having an affair and visits a psychiatrist, but eventually she rejects both of these ''solutions'' and decides that she has the ability and the resources needed to work out her problems herself. In the end she and Clay do work them out together. What ultimately brings harmony to the home is communication. Molly is transformed from a silent partner into an active partner in her marriage.

In real life, too, Mrs. Greber sees communication as the means through which family members can find solutions to the problems caused by career and corporate demands. Until corporations begin taking a more humane view of the problems continual relocations cause people, she feels that the problem-solving must begin with the individual families. And this may mean getting off the ''fast track'' or leaving the corporate world.

Family members must decide what they need, what they will sacrifice, and what they will compromise on, Mrs. Greber comments, and the time to do this, especially in a two-career marriage, is before the wedding and continuously thereafter.

The novelist concludes, ''I would love to see people talk to each other and to their kids, and to be honest. And if they do, I think we can change some of the statistics around.