Hi everyone. New here and really needing help! My 1983 720 with z24 engine is now emitting a rather large cloud of white-ish smoke from the tailpipe along with a black somewhat oily feeling substance. I'm not sure what's wrong! All started when I went to back out of a parking spot (3 speed automatic), and heard a loud pop. Not a backfire but more like a crunch... Then there was smoke. I had experienced smoking before, only when I was idling a while in a fast food drive through or sometimes at a red light, but I always thought it was the driveshaft rubbing against what's left of my warn out carrier bearing.. everything I've researched says valve seats, head gasket, but I'm not getting any oil into water or water into oil and the motor seems as strong as it ever did. The transmission has trouble going into 2nd and even harder to get it into 3rd, and I'm losing Trans fluid somewhere but no signs of a puddle when parked. The only times I've driven it since the pop was after replacing all fluids and filters to see if that would make it shift right and quit smoking. Any input would be greatly appreciated.

gonejohn5k wrote:Hi everyone. New here and really needing help! My 1983 720 with z24 engine is now emitting a rather large cloud of white-ish smoke from the tailpipe along with a black somewhat oily feeling substance. I'm not sure what's wrong! All started when I went to back out of a parking spot (3 speed automatic), and heard a loud pop. Not a backfire but more like a crunch... Then there was smoke. I had experienced smoking before, only when I was idling a while in a fast food drive through or sometimes at a red light, but I always thought it was the driveshaft rubbing against what's left of my warn out carrier bearing.. everything I've researched says valve seats, head gasket, but I'm not getting any oil into water or water into oil and the motor seems as strong as it ever did. The transmission has trouble going into 2nd and even harder to get it into 3rd, and I'm losing Trans fluid somewhere but no signs of a puddle when parked. The only times I've driven it since the pop was after replacing all fluids and filters to see if that would make it shift right and quit smoking. Any input would be greatly appreciated.

Is there a vacuum line going from the transmission to the intake manifold, I ask because I don't know about automatics, but if it does have one, I would suspect that the intake manifold is sucking transmission fluid out of the transmission into the intake, and that would be what the cloud is.
Perhaps you can disconnect that line if it has one, plug the part coming from the intake so that there is not a vacuum leak and start the engine up and see if it clears, you will not be able to drive it that way.
If that is the issue, you will have to replace something in the transmission that has sprung a leak, perhaps whatever diaphragm that tells it when to shift.