Well, it's not hard to do but it's really easy to bugger up the door panel
and fasteners if you don't know what you're doing. Odds are the retaining
clip has broken. A bodyman could do it quickly and cheaply.....

It is probably not off track, it is more likely that the gear inside the
motor housing is bad.
they are usually made of a plastic and are mounted just inside the motor
cover. there is a 3 point assembly inside the gear which dampens the motor
stop and this goes bad. it is part of the gear you buy and the whole thing
is replaced as one assembly.
It is not hard to do, but requires the door motor be removed.
i just did it in my truck and instead of drilling out the motor rivits, i
just took a cut off wheel on my grinder and ground the metal door panel with
a circle over the motor /gear housing and removed it easily.
as he said, watch the door panel clips and retainers. otherwise it was a 45
minute job for me.
old john