Change in shifting after oil change.

[settle10]

Last week I changed the oil in my standard tranny. It was sluggish in the mornings until heated up and was not smooth when shifting into reverse. It called for standard 30wt oil and I used Mobil 1 10W30. Since the change it shifts into reverse smoother and is not as sluggish in the morning but its has some resistance when shifting into 2nd. Once it warms up everything shifts great. Why the change when shifting into 2nd. I also cleaned the tranny area with an engine cleaner, but I can't see where this would cause a problem. Should I give it some more time or look for problems.