727 issue

I have a 73 Chrysler Newport 2 door hardtop and the trans feels stuck in 3rd. If i try manually shifting in first or second it feels like the parking brake is on. The PO had the kickdown linkage all messed up after installing it to work backwards after a carb change. I have since fixed this issue with no change, I also noticed it feels like its holding back under takeoff and after it gains speed and you let off the throttle a bit it releases if that makes sense. I have scoured the internet for days trying to find a related problem but have had no luck, Hopefully someone here can steer me in the right direction. Thank you.

not exactly the same prob,BUT i had one that would not shift into third (new build) unless i let of the gas then it would engage.turned out to be the linkage adj. it was very crucial to have it EXACT.

I'm beginning to wonder if the first and second are in need of a rebuild. Was trying to avoid it but it may be the only way to fix it without troubleshooting for days.

Could be a slipping rear clutch, it's used in all forward gears. Sometimes that clutch will slip under the load of acceleration and then engage when the load is decreased (throttle lifted). If that's the problem, it's gotta come out.

Older post so I'm not sure if you have already remedied the problem. Knowing that someone else drove the car with the kickdown linkage messed up, the first thing you need to do is drop the pan and see what kind of trash is in there.Driving that big heavy car with K.D.linkage way out will eat the friction surfaces on the bands and clutches and overheat the other related surfaces.Had a very similar issue a long time ago. Dropped pan/fluid,drained converter,checked both bands integrity,and adjusted both bands to factory specs.I did alsoswap the valve body out with another similar, known good unit because of all the trash that was floating around,plugging up all the small orfices. Refilled trans to the correct level (hot and in neutral not park). Checked kickdown linkage and drove it around for the next couple years as a grocery getter, luckily avoiding a rebuild. Not every situation turns out so well,so easily and inexpensive, but it is so worth the effort. I opted to swap out the valve body instead of trying to flush the original unit as I had several used units laying around and thought it would ensure that I wasn't experiencing a plugged up V.B. Hope this helps. Bill