Help doing fluid level check n Trans up keep.

My girl friends Jeep seems sluggish n
pulling to many Rpms n not putting down
enough Mphs. Plus l m almost certain l m
hearing a whining. The jeep has no dip stick
for Trans fluid. So l can't really tell what
kinda shape fluid is n. Its a new one on me
all around. Never seen no dip stick on an
auto trans vehicle before. The tube is there
with a cap. So u can add to fluid level. Any
tips? Really m not one to dip n pocket for a
mechanic. I won't own anything l can not
repair myself. I m just at a lose here. I m at
point where l m going to drain all the fluid n
replace filter n or mesh add brand new trans
fluid n go from there.So is they an light
indocator for low fluid? I mean really? If so it
doesn't light up with the flip of ignition.