I have a 2001 Windstar with 57K miles. I took it to a shop they changed the transmission oil and filter. They replaced the oil with coastal synthetic blend mercron v. The transmission does not slip into any of the gears. It shifts hard from 1st to 2nd. There were no metal shavings or burnt fluid before taking it to the shop. It stays in 1st gear longer than it did before it was worked on. And when it goes to 2nd it lunges. Could this be a problem from the parts or something internal? The guy at the shop wants to pull the transmission and rebuild it but I don't think it needs rebuilding. Any response would be appreciated.

PS Parts came from AutoZone. I was not happy when I found this out.