!!!! 4L60E transmissio question !!!!!

[MAC67]

ok lookin for the guys that know theyre stuff on these and problems they have , my wife has a 95 ext cab 350 4x4 with the 4l60e in it , i am not real familiar with these transmissions but this is the problem , if i pull the gear selector into 2nd and attempt to take off it slips , if i pull it into first it will go just fine , seems to stay in 2nd a little longer than it should , and all the other gears are fine , it is just that when i pul it into 2nd manually it seems like it trys to take off in second gear and slips ,, any ideas or fixes ?????? transmission was rebuilt by a shop last year , or a new one was put in im not for sure , previous owner had it done