Transmission shifting with A/C on?

Something weird developed in my '03. With the A/c engaged, and foot on the throttle, I can see and feel the RPMs shoot up about 200-300 every 14-18 seconds. I'm assuming this coincides with the cycling of the A/C compressor. It feels like a downshift/upshift in a matter of a second. This can't be normal because it never did it before a month ago. Any ideas? Windstar has got about 36k miles on her. Thanks.

I would check the AC freon level ,could be kicking off and on because of a slow leak.. There is also a pressure switch that goes bad on these windstars.

I would check the AC freon level ,could be kicking off and on because of a slow leak.. There is also a pressure switch that goes bad on these windstars.


It was because of the refrigerant being low. O ring went bad and refrigerant leaked out. Too weird that it would cause the tranny to shift though. Does not happen on the Explorer.

The saga looks like it may continue. Was out and about a day after they "fixed" the problem, and it was doing the same thing. A day after that I didn't feel anything. Don't know if it's going to turn out to be an intermittent issue or not, but you bet it's going back when it starts doing it regularly.