Burned out the second transmission on my 89 100. I had a used transmission
and transaxle put in about a year ago, and it's been acting up for about the
last 6 mos. Reverse slipping when hot, and some times downshifting from 3rd
to 2nd at road speed unnecessarily. Then it is difficult to get back into
3rd, without slowing way down. I put up with this until now, it will hardly
go into first gear from a standing start. I can drive about a block in
first, and it is slipping so bad it won't move at all. Fluid is red, but has
graphite-like particles in it, making it look dark. The fluid does not smell
burned. I have used  2 doses of Lucas Trans Fix in the past 6 months, but
didn't seem to help much.

I know I need a replacement automatic section, but my mechanic doesn't have
a used one available. What are the best sources for a good used autobox for
this car? There is one on eBay for $400, but I am wary of buying something
like this on eBay, not knowing if it will work when it gets here! Shipping
alone is $200!

Any suggestions? Thanks in advance for your advice!