The gears show wrong in your 97 Grand Marquis could that have something to do with the transmission?

If by show wrong you mean it tells you your in first instead of second gear going down the road that could be a simple fix. Theres a sensor on your shift linkage that tell you what gear your in. it that's out of broken it could just tell you your in a different gear. As well as if it will lead to the down fall of your transmission i'd have it checked it should pop up a check engine problem usually and your local autozone can asses the problem for you.