I have a 1978 GP, with an 81-85 307 Oldsmobile (Vin Y or Vin 9 with 5a heads), hooked into a TH350 which is hooked into a 7.5" rear end. Since the beginning of August, I have taken the car from not running and rotting away, to running, stopping, driving and so close to what I would consider done, prior to me selling the thing to the next owner.
Anyways, when I first looked at the car, I noticed it was leaking ATF pretty aggressively. Because I refused to toss cash at it without making sure it ran, I ended up tossing 2 different drip trays under it and forgetting about it for a bit. I continued to work on things on the car and the drip tray's I used both had a significant amount of fluid in them, however, some of that was water from a few rain storms, leaves from various trees, some oil, some brake fluid, some gasoline, some brake cleaner etc. Basically they where under a leaking car while I worked on it. The trans fluid was right in the hash marks, but started much higher when I got it (I figured it was just over filled).
I sprayed the pan with some brake clean and the leak actually ended up stopping after that. Fluid level still in the hash marks. I diagnosed some issues and took the car for an initial test run. I noticed that shifting from park to reverse was fine enough, but if you moved the shifter around (console shifter not column of course) it would drop into neutral. After that, you could shift to drive and it would sometimes engage, sometimes it would sit in neutral requiring another pullback to get it to engage. I drove it a little distance, slowly, getting up around maybe 25-30 mph, and it wouldn't shift up. So I limped home. The trans fluid is now at the bottom of the hash marks, but still in the correct level, getting close to "add 1qt" or whatever it was. Last night, I drove it again. This time getting it up to a blistering 35mph, which caused it to upshift 1 time during this process, but everything seemed fine. I drove it home, check the fluid and now I can't even see a level, appearing to be completely empty (no burnt smell no nothing and the fluid was nice and red before).
I know the pan is leaking. I am going to be replacing the gasket and cleaning the pan out, along with the filter/magnet (or replacing) however I have been told that cleaning out a neglected TH trans and putting in new fluid can cause more problems with sludge/debris being push around. As for the shifting issue, I am unsure if this is a vacuum modulation issue, the trans being warn/low, the Kick down cable being trashed (which wouldn't explain to me the weird engagement) or maybe something else I am missing. I am trying my very best to wrap up this project to sell, since I no longer really have space for the car, at least right now, and the snow is about to fly.
Anyways, when I first looked at the car, I noticed it was leaking ATF pretty aggressively. Because I refused to toss cash at it without making sure it ran, I ended up tossing 2 different drip trays under it and forgetting about it for a bit. I continued to work on things on the car and the drip tray's I used both had a significant amount of fluid in them, however, some of that was water from a few rain storms, leaves from various trees, some oil, some brake fluid, some gasoline, some brake cleaner etc. Basically they where under a leaking car while I worked on it. The trans fluid was right in the hash marks, but started much higher when I got it (I figured it was just over filled).
I sprayed the pan with some brake clean and the leak actually ended up stopping after that. Fluid level still in the hash marks. I diagnosed some issues and took the car for an initial test run. I noticed that shifting from park to reverse was fine enough, but if you moved the shifter around (console shifter not column of course) it would drop into neutral. After that, you could shift to drive and it would sometimes engage, sometimes it would sit in neutral requiring another pullback to get it to engage. I drove it a little distance, slowly, getting up around maybe 25-30 mph, and it wouldn't shift up. So I limped home. The trans fluid is now at the bottom of the hash marks, but still in the correct level, getting close to "add 1qt" or whatever it was. Last night, I drove it again. This time getting it up to a blistering 35mph, which caused it to upshift 1 time during this process, but everything seemed fine. I drove it home, check the fluid and now I can't even see a level, appearing to be completely empty (no burnt smell no nothing and the fluid was nice and red before).
I know the pan is leaking. I am going to be replacing the gasket and cleaning the pan out, along with the filter/magnet (or replacing) however I have been told that cleaning out a neglected TH trans and putting in new fluid can cause more problems with sludge/debris being push around. As for the shifting issue, I am unsure if this is a vacuum modulation issue, the trans being warn/low, the Kick down cable being trashed (which wouldn't explain to me the weird engagement) or maybe something else I am missing. I am trying my very best to wrap up this project to sell, since I no longer really have space for the car, at least right now, and the snow is about to fly.