yorktown5,

I was driving a POS rental Ford Taurus that had the same symptoms. In one day of driving the damn thing just got worse!

At first it would shifft kinda hard into first then I noticed that when I floored it, the trans slipped as the revs rose in 1st gear then as it was about to self destruct, second would engage really hard that the front tires would chirp.

Then it just got worse and all the gears started doing that.

Never really knew what was wrong but I knew that the transmission started leaking some transmission fluid.

..just to make sure, have you checked the transmission fluid level with the transmission and engine up to operationg temp (and engine on) w/ the trans in P?

If the door locks don't work, for the time being I'd disconnect the line and plug the engine side fitting. You can fiddle with that later, shifting is more important.

However, a vac leak will make the tranny shift hard, not soft.

Disconnect the line on both ends and make sure you can blow through it 0-- if it is plugged, it can act as a one-way valve and hold high vac all the time.

Peter

Update:

I had vacuum. It was easily detected by putting my finger over the hose at the modulator while the car was running.

In talking this AM to the shop where I bought the modulator, the stuck pin is normal. Locktited in place in this vintage.

Peter's comment about hard shifting being a consequence of a failng modulator struck a chord. For a day or two before the tranny started slipping, and for a cause at the time I attributed to a poorly set kick down linkage, the car did exhibit much harder shifts, one more noticable was a decided thunk when dropping back into second at a stop. And I was actually "getting rubber" on upshifts when accelerating agressively.

Cranking the new modulator's key in a few turns and then driving, cranking some more, driving again etc. caused VERY minimal improvement.

So...what I now think happened is the modulator finally failed causing hard shifts, and lockup was so dramatic it fairly quickly (while I was focused on the overheating/radiator problem) caused something to "give" inside the tranny.