Hello everyone. Been a while since I've used this forum. But I have a 1985 300sd with a 722.315 trans in it that's had an issue since I bought it last year. And it's been sitting. But its only got 101,000 on it and I'm not sure why its flaking out on me. I'll be driving it and it'll go from 1st to 2nd no problem, then when it should be shifting into 3rd it just kicks out and slips like a hippo on ice. If I floor it, it does try to downshift. I've repaired all the relevant parts of the vacuum system and played with the modulator pressure properly and improperly. Oil levels good. Shift linkage is good. Bowden cable's good as far as I can tell. No change in behavior.

Any ideas?

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Matt.

When was last time fluid and filter was changed? When filter is neglected it can suck out of it's shell blocking fluid from circulating through transmission. If that makes any sense. This was the case with my filter on my recent purchase of an 85 300DT, which I am hoping was not the death of my transmission that will not shift to 3rd onto 4th like it should. This is an issue I am trying to sort out currently. I have a good spare trans but trying to avoid swapping them as I really think I knocked something loose while cleaning engine and trans from an old oil leak which has everything coated. It shifted before cleaning (if you want to call it that) but was acting up which is why I changed fluid and filter as recomended where I should start in trouble shooting trans. Once I am finished double checking vacuum system and making sure bowden cable isnt disconnected. My step will be removing valve body to make sure nothing pulled into to it from filter causing a stuck valve or spring. Not looking forward to it but I plan on trying everything before swapping trans for no reason.