Tranny Slip???
 

I have a 2002 Chev Silverado LT ext.cab 4x4 with a 5.3 and a 3.73 rear end. I purchased this truck last fall with fairly high kms (225,000kms or about 140,000 miles). The truck has always shifted firm from 1st to 2nd or from 3rd into OD but other than that its been fine. When i bought it the guy said it was "chipped", i dont know if that has anything to do with the firm shifts. When i got the truck i had the tranny flushed, new filter and synthetic fluid put into it. I noticed in the winter when it was cold out the truck would lurch forward when cold when i started it. That seemed to go away with the warmer weather. Today when i started up it did this lurch thing again and when i was bringing up the truck to highway speed the engine screamed before shifting into 3rd and having troubles pulling from stoplights. Any ideas folks???