Volvo: 2000 volvo s70, volvo s70, volvo dealer

Question
I just purchased a Volvo S70 and after driving it for approximately 40 miles the transmission warning light came on, the check engine light came on, the car drives fine but sometimes it slams into gear from 1st to 2nd gear. I checked the codes and it has two: P0713 & P1618.
I called a volvo dealer and they suggested to: 1.- flush trans if it did not work 2.- Replace valve body/trans speed sensor and that does not work 3.- Replace transmission... It sounds like a lot of guessing to me and I'm trying to get a second opinion, do you have any suggestions????

Answer
Lance,
The transmissions in those cars has been a problem. Yes flushing is good but mostly before a problem occures, a form of maintenance.
When even I have a car that the trans slams I go for a replacement. The damage is done. I have on two occasions put in the three trans solenoids and those cars were fixed, but those cars did not slam into gear they just did not go into torque converter lock up.
Save the money on the flush and valve body and put it toward the reman trans.