97 blazer shifts hard

[Invictus]

i recently purchased a 97 blazer and a few days later it started to shift very hard from 1st to 2nd hard enough to bark the tires under half throttle the 2nd to 3rd isnt as bad but it still hits harder then it should and it shifts perfect from 3rd to 4th...also i found a receipt in the glove box that showed the tranny had been rebuilt 20,000 miles ago so i dont understand how it couold haver any tranny problems....if anyone has any ideas on what it could be please let me know .....thanks

[Invictus]

no ideas??? well i forgot to put that it has 154000 miles on it but only about 20,000 on the rebuilt tranny...also got a new problem....there is a squeak comming from the engine but its not comming from any of the belts or the compressor ....and about the time the squeak started the check engine soon light came on....if anyone has any ideas on either problem please let me know ....thanks