Transmission Problems

I Have A 2000 Pontiac Grand Prix Gt With Approximately 113,000 Miles. I've Only Had The Car For 10 Months. I'm Currently Not Even Driving The Car Because The Transmission Has Been Acting Up For A Good Month Now. When Taking Off, It Changes From First, Second To Third Smoothly But Never Shifts Into Drive!! On The Interstate It'll Turn 3000+ Rpms Constantly. Once The Car Has Been Traveling For At Least 15 Minutes It'll Start A Whining Sound. When I Let Off The Gas The Rpm Gauge Immediately Drops Down To 1000+- Rpms And As I Give It Gas It Takes A Minute For The Rpms To "catch Back Up To Speed". The Fluid Has Been Changed And Even Replaced A Speed Sensor But No Improvements.
Another Issue Is A Popping/cracking Sound When Taking Off Or Letting Off The Gas. Sounds Like Something's Going To Break Loose Up Front. I've Had New Axles And Shocks Put On Prior To This Noise.
Any Suggestions Would Greatly Be Appreciated. (besides "sell It"). I Plan On Doing That - If Possible.

Sounds like you have a problem w/ the torque convertor or possible even the flex plate. Have you hooked up a scanner to it and monitored the gear changes?? Thats the best way to see if its going into 4th. It might be going into 4th but not locking up the TC.

Cracking noise makes me think the flex plate might be broken too. I've heard of people breaking those w/ high HP motors. So maybe the TC took a dump and took the plate w/ it.

Hope this helps.

Tim

Thanks for the info.
I took the car to the local dealership and had them run a diagnosis test. I was told that it shows to be changing into 4th. However they did find a bulletin out on the car. But they first recommended a trans flush and if that doesn't help then according to the bulletin it may need a valve body and PCS & TSS replaced. This was estimated at $777.
This was on July 27th and I can't remember what the PCS & TSS stands for. I had them do the transmission flush but I've not noticed any difference. I'm still driving the car though - it drives and shifts (thru 3rd) smoothly. I don't know what I'll do with it.
I appreciate your time.
Lori

PCS = pressure control selonioid

If anything I would try this first. If I remember right it does not require the trans to be torn apart to replace the PCS.

http://www.intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=GMH-PCS&Category_Code=T

Maybe TSS is TCC

http://www.intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=GMH-TCCS&Category_Code=T

i build this tranny all day at work and they are known for a drum inside to crack and couse this problem.and the only way to fix it is to pull the tranny and replace it.not good news but it shouldstop the wondering.