02 transmission

i have an '02 malibu with 51,000 miles. this week i've started having trans problems. when gears are changed it makes a loud noise and kinda pops. there is even a little jump when put into rev. and drive. it's not as bad when the car is already in drive and switching gears as i go down the road. i'm completely stupid when it comes to car stuff but, it is my understanding that my trans is "a nonservicable unit". that's what the precision auto guy told me today when i took it in for an oil change and to have the fluid checked. he said that i may need a new transmission. please help me!!!!!

My 01 Malibu trasmission had a check engine light on, I had it scanned for free at the local auto parts joint. The scan read out as a bad intake air temperature sensor. I replaced the sensor, $15.00 and 2 minutes to plug it in to the black air intake tube after the air filter box. I still had the same symptom of the transmission banging hard when put in to drive or reverse and very hard shifting through the gears. Further research showed the problem was in the 2-wire harness/plug assembly that plugs in to the air intake temperature sensor. I replace the harness/plug assembly and symptoms of banging in to gear and hard shifting went away. Check around, most big auto parts stores now do scans for free.

thanks, i was freaking out thinking that i needed a new transmission like the precission guy said! glad i took someones advice and searched it here first. now i have enough info to give whoever fixes my car!