[tuneup427]

I bought a used th400 to rebuild. The previous owner had rebuilt this unit but only put 17 miles on it. He had done something wrong and just opted to replace it with a factory reman unit. I started tearing it down and all the fluid was a good red color except the fluid in the servo. It was pitch black. The band and drum look good. So far all the clutches look new. What would cause the fluid in the servo to get so bad. Obvoiusly something is wrong.

[71 nova]

Did you check all the seals ? Making sure they are facing the right way ? You can air check the clutch packs to make sure they are ok. the black stuff could be a seal ? Or maybe for some reason the valve body or case had some dirt in it that was not cleaned properly ? I would say in your case take it down and check everything all air checks, clearences, make sure the front pump drive tangs are correct too. What were the symptons ?