Alicia,
When you did a suck assessment, was it nutritive or non-nutritive sucking?
Sometimes when we do a digital suck assessment with kids who are having
swallowing difficulties, they will seem fine unless milk is delivered (e.g. by
syringe and tube or eyedropper), then the suck will disorganize, or gulping
will be audible, etc.  I have seen quite a few of these miserable until they
latch well babies, it is very hard on mom.  Some have had transient
difficulties transporting a bolus of milk for swallowing, others have had
trouble drawing the nipple sufficiently far back in the mouth to trigger the
suck reflex, and came off after a feeble attempt to suck; others were just
sensitive kids who got disorganized readily.  Feeding early will often assist
by keeping baby from getting too impatient.  Other things that might work:
rocking or bouncing baby, using a fast, small motion while holding baby firmly
against the chest or shoulder to increase organization before feeding; have
mom attempt to latch baby on while she stands or leans back (yeah, I know this
is a big kid, a babysling may help provide support), this decreases choking;
and a recent discovery: have mom tickle baby's lower lip with her nipple to
elicit a gape, but not pull his head in, let him move his own head forward.
And encourage her that this problem is frustrating, but usually temporary.
        What do you think, does any of this fit?  Keep us posted,
Catherine Watson GEnna, IBCLC