I’m at a loss
 

So I have been fighting with this 07 Pacifica and can’t seem to fix the right thing. I have replaced a lot of stuff starting with the coils nd spark plugs, alternator then the o2 sensors. I have checked my fluid levels and all are at proper levels.
After I have done this work the problem goes away for a few hours (it shifts properly) but if I park and turn the car off the problem comes back. Last night after I got done working on it I went to start it nd a whole bunch of smoke comes from the exhaust. So now I have a blown head gasket I’m gonna say!!!! I put some k seal in and everything. I noticed a lot less smoke then before after I finished with that I drove it without a problem till I got back home. I had to run down the road and the same sluggish, not shifting to right gear. I don’t know what to do or what it is plzzzzz HELPPPPPP

well smoke from the tail pipe and transmission shifter issues are two completely separate issues. you need a scanner that can get into the transmission computer and see what the codes are before anything is done.

What color is the smoke, white points to coolant, blue points to oil, black points to gas/fuel?