94 firebird wont shift into low

Have 94 firebird auto transmission that will not shift down into low. When manually shifted to low car will not move.

Runs fine when starting in second

Any ideas?

Thanks

Your first gear is gone.... the rest of the gears prolly soon to follow....that would be my number one guess just from what you have told me

should have mentioned its been that way for 6 years. runs fine but it starts in second ....

thanks