Transmission ?'s (Temp guage & shift problems)

Hey everyone...
This is my first time writing to one of these forums, so bear with me. I have a 2003 Silverado 2500 HD. It has a towing package and subsequently a transmission temperature guage. For much of the first 9mos. that I had the truck, the temperature never seemed to climb above 120-130 degrees, however, now, it is not uncommon for the temp to climb up to 160 degrees under normal driving conditions. The guage runs from what looks like 120-125 up to I think 250, but I'm not sure (I'm not down by the truck right now :). The driving is under normal city/suburb driving in 2wd, however no towing/no load in the bed. I have had problems with a Dodge 2500 in the past (with shift problems) and that's why I went with the Silverado instead of another Ram. Should I be concerned with the transmission guage or is this something that I can attest to a break-in period, etc. Also, the transmission doesn't seem to shift as smoothly as before. On a straight/no incline pavement, it seems to rev to about 2800 - 3100 RPM, drops down to approx. 2700 RPM and then shifts down to 2000 again where it finaly shifts. It seems like it sticks a little, but again, I'm not the expert. Any ideas? My main concern is that I want to make sure this gets fixed before the warranty is up. Hope you guys can help.

Yes sir take it back and get it serviced it sounds like something could be wrong although im not for sure cause im not driving it. It could also be because the tranny you have is the 4l80e which alot more power robbing because of the size gears and soforth but anyway you cant really tell so take it in while you still can worst case scenario they say nothing is wrong and you drove for nothing but if there is something wrong you want it fixed ASAP b4 it starts to tare your gears up!!!