[valiant67]

That screw style design was used for years, and as they age they get very stiff, being all metal. you can feel it when you try to lock/unlock the door manually.

I ended up replacing mine in my '89 Lebaron with the newer style low-friction (mostly plastic) ones out of a AA body. They worked much better, especially in cold weather or when the car had sat for a while and the battery wasn't at it's fullest charge. They were a direct swap-in except for the electrical connector. I used the old lock actuators and the pigtails for the new ones to make short jumpers.

Thanks for that information - I think I'm going to see if this possible swap applies to my old RWD cars as well since the power locks often don't work and they have that same stiff feel to the manual lock/unlock (sometimes to the point only the key will lock or unlock the door).