tell us how many bolts you did take out, and recognize there may be some longer threaded studs that are also part of what holds this unit together. you will remove the nuts to these studs.
Do not pull both sides at the same time, and you should use a floor jack (and someone who has done this particular job on one of these trucks) to support the unit as you pull it out, it will be heavier than expected, and awkward, and the second it pulls loose. it will want to shift on the jack, it can take your manhood, your fingers and toes, and your internal organs with it, if you are not really aware of how and when it will shift.
Be careful doing this job. I never send someone to do one of these who has not done it before with close supervision