75 Dart with /6 and 904,is not wanting to start in park, which plastic part is usually the one causing this, and can they be found anywhere? Thanks.

The plastic bushings support the linkage shafts, if they're worn or fall out the gear positions will be incorrect. Originals are usually white.

I would undo the linkage at its' easiest junction to come apart (as you know some of those press in bushing are TIGHT) & move the flat horizontle lever to park & neutral & see if the middle pin has continuity to the trans case & if all good there then see about a slight adjustment to the linkage or the bushing as needed.

It starts fine in neutral. John, is that the full part number? Thanks

Yes, dealer should have it or E-bay.

All those linkage pieces have a little slop in them. Add up all the connection points and the slop can be quite a bit. I believe there is a specific adjustment procedure so all the slack is taken out. That can cause the vehicle to start in neutral but not fully engage PARK.

Make sure you take all the slack out of the linkage when you re-adjust it. Also, check the pivot shaft itself for wear. Not only was my bushing ovaled out, the pivot shaft was worn where it rides in the bushing. I had to build the area back up with weld and grind it back down.