my transmission was knocking for alittle while like a month i figured it was something else but I recently noticed my trans fluid was low and thought this might slove the problem

I would continually check the Fluid and make sure there are no leaks. Make sure there isn't a Check Engine Light on. If it continues to give you trouble you probably need an Transmission Expert to look at it.

I just thought it was a bad manifold but then had my dad looK and he said your low on trans oil pretty low so we added some.. and it's been awhile cause I wasn't sure what it was myself but we added more new oil today so I figured they could be alittle dry cause didn't have enough oil so maybe the knocking will go away, it's only for about 2 3 minutes when I crank it up then after it heats up its gone

a converter bolt at flywheel may be bumping the bell housing