I originally had 2 female sugar gliders that came with each other and lived together with no problems for 3 years. One of them recently passed away and I was worried for the other one's health so I got her a female companion. After the 30 day quarantine I introduced them and the new glider seemed very affectionate and clingy. After monitoring them in a cage together for a couple of nights the new glider is riding on the back of the older one and they are crabbing at each other. There isn't any blood or bald spots but her neck is a bit wet. The older glider doesn't seem interested in playing with her but when I separated them the new glider was very stressed and wanted to be with her. I am not sure what to do I am very worried about them are they not going to bond? Please help!

ok, so after quarantine you do not introduce them. (there is a procedure write up
somewhere on this site and others on other websites.) you start scent training to
get the gliders used to each others smell. I swap pouches every 2 days. I also provide two pouches for each glider. I check to see if glider is sleeping in clean
pouch or the one with the other gliders scent. Its a good sign if they choose to
sleep in the scented pouch. I continue this for several weeks, if I notice the
gliders always sleeping in the scented pouch then I move cages closer, but keep
them 6 inches apart or more so they cant grab a tail.
then finally my wife puts them in the tub. one cage is cleaned to remove most
of the scents. if they behave in the tub without fighting we put them in the clean
cage so they can mark it together. FIGHT is fast and ugly, think of two cats going
crazy at each other, during tub time sometimes they have small spats till they
work out who is who. we have a clean pouch and if they go into pouch together
without fighting that is good. PS clean pouch goes in tub after some time of them
not fight, and being ok with each other in tub.
I don't know how much yours were grabbing at each other, but some of that is
normal for me. I have 6 gliders in my colony and the alpha likes to sometimes
bully others during treat time. he will even chase them around the floor some, but
none are harmed. And usually they come back to me, friends again for another treat.
but alpha gus is always ready to bully someone who tries to treat steal.

anyway... If you see no injury on either glider, and the crabbing was not to
strong. again mine have spats and squabbles, in pouch they can get grumpy and make
noise. maybe a foot in face, or a hard groom. I would put your gliders back
together and keep a close eye out. If they are crabbing strongly at each other and
getting nasty, I would do scent training.

last example, during dinner time, riggs has trouble getting corn out of bowl, so
he will try to steal another gliders corn, this creates a few seconds of hard
squabbles and nasty squeek and then over once the corn is saved or stolen. so I
usually hand riggs a piece of corn so he gets his share.

good luck.