Ford Repair: 94 Cougar - slipping auto trans, vacuum modulator, vacuum lines

Question
Hi Ken,
I have a 4.6L with 42K miles. Yesterday morning I drove 65 miles to an nearby town and came back mid afternoon. About 20 miles from home the transmission slipped and the tach reved up a couple K rpm, then in a second or so it reingaged. This happened between 65-70 mph and occurred four times. I dropped down to 55-60 mph and made it back home without any more "events." The fluid is pink, but slightly too full (I checked it in park w/ engine idling on level ground). Is that the problem, too much fluid? Is it just the heat (over 90 yesterday afternoon)? Should I put in new fluid and filter? Maybe something internal?
Thanks for any input or ideas.
Blanche O'Quinn

Answer
Ms. O'Quinn,

I would first address the fact that your transmission fluid is too full, which is as bad as being too low. Also it would be a good idea to change the transmission filter, which is located in the pan.If you are still having trouble after all this, check your vacuum lines going from the engine to the transmission. Also check the vacuum modulator. Hope that this helps and if you need further assistance, please do not hesitate to contact me. Good luck.

Ken