Lucas it is worth a try. Just suck out as much of the reservoir as you can and put the whole bottle in there and top off to the correct mark with the correct ATF.
If you have to do a replacement make sure it is not a rebuilt rack but a re-manufactured rack from a reputable builder with a warranty for parts and labor like 12months or 12k miles. There is no need to go new. And when replaced make sure they use the correct fluid as I note in posts above. Follow the maintenance I note with partial fluid changes.