check trans flashing

Have a 95 v6 passport with the check trans light flashing. i believe it is in back up mode. I know the manual says to take it in asap. My question is are there other things that could cause this to happen before i get raked over for major work at the shop? Passport has 126000 miles and im not sure of its prior tranny servicing. got it not too long ago its always ran good for me and appeared to be taken care of. I will say the first i used its 4wd was recently too. seemed to work fine but not sure if that aggrevated something. thanks for the help.