transmission issues

[christopher]

i had the tranny mt643 rebuilt about 20k miles ago, the fluid was black like tar. turns out its wiped out. i wonder what the first person did wrong(out of business).
nice to pay for work twice
chris
mci5c

[TomC]

I believe the oil change interval on that transmission is 12,000 miles-might have waited to long to change it.  Good Luck, TomC