Originally Posted by mmerlinn
Huh? The transmission fluid is separate from the transfer case fluid so HOW does filling the transfer case have any effect on how the transmission shifts?
I think he is saying the TH400 is leaking ATF into the Dana 20.
Anyway the dana 20 takes gear oil. I am not too familiar with the TH400/D20 combo so I am not sure which one and maybe both have had a seal failure. A lot of the time the only seal is on the T-case input shaft, but some trannys have an output seal too. Whichever it is, you can replace the seals after you seperate the case from the trans.