when I first start my car up in the morning and start to drive it shifts funny from 2nd into 3rd it's only the first three times it gets up to 40 miles an hour. After that, its fine for the rest of the day. Its an automatic with 134k. What can i do to fix this?

 

My 04 OZ (250K+) also shifts funny. Cold, from 2-3 and 3-4 it shifts hard. Warmed up, it shifts smooth until it gets very hot (Phoenix gets HOT) and then it overruns from 3-4. Downshifts are fine.

I'm suspicious of the speed sensors when cold, and it needs a fluid change. I'd like to improve on the transmission cooling to rule that out also, but it is old.