First off 97 Trackers came with 4 speed transmissions,
secondly, if it wasn't slipping before the trans fluid change
and started after, it's a sticking valve body, not clutch packs
as your "trans spesialist" said.
Now I don't know how mechanicaly inclined/declined you
are, but I know if you have the mechanic spirit you can rebuild
the valve body, there are lots of parts, and little balls, but it's
a doable job.
I did my brothers trans (95 4 door) he was mad after changing
the fluid and it started slipping, so we pulled the valve body, got
a gasket set for a Toyota, (same trans brand) and cleaned and
replaced all the gaskets, and found little bits of gasket and junk
in the workings that were the problem.
Now the trans works great, he just drove the Trucklet to Utah,
about 900 miles round trip with no problems, so look into that
don't get ripped off, find a shop that will just do the valve body
or a friend that is a backyard mechanic and get your trucklet back
on the road, I think the gaskets will cost about $50 max, and it
has everything you need, plus some additional stuff for other model
trany's too
Good Luck
Wild