Hey, I'm new to pontiac. I recently sold my jeep and bought a 2002 grand prix gt, 3.8l series II engine.
I paid $1350 at a used car lot with no warranty. I did look the car over, and test drove it a good while around town. Only things I noticed wrong were the front passenger side window wouldn't roll down and the drivers side front rotor was warped and glazed. There's 2 new tires on the front and all new brake pads on front and rear. The AC doesn't work. The body has NO RUST (I live in Michigan). The undercarriage has usual surface rust in some spots but not bad at all. Really the only body issues are the front bumper has a small crack and some scratches. The passenger fender has a ding. I didn't notice any engine issues or tranny issues.
Here's the issue:
After extended driving one day, I noticed the transmission whining. It wasn't too loud, but enough to feel it in the steering wheel and I could hear it with the window down. My shifts didn't seem off, and I didn't feel any thing going wrong. The car continued driving just fine with the whine. The following night I drove for 90 minutes straight, on the freeway, on main roads, all over town, and the whine never appeared. The next day I drove 20-30 minutes and the whine appeared again. For a few hours that day I drove around experimenting, and I noticed the whine GOES AWAY after I turn the key off and then back on. Anywhere from 3-20 seconds after turning the key off and then back on, it's GONE. It reappears AFTER I drive it for a bit, and it appears to come back sooner when the car has been warmed up. On any initial cold startup, it feels like it takes a while for the whine to appear until you drive it for a while.
I took it to a transmission shop, the the guy there hooked up a big scanner and drove around for about 10 minutes. He came back and said he couldn't feel or hear anything wrong, and that the car was really nice and drove wonderful. He did mention there was a code for the MAP (NOT MAF) sensor and another I believe he said STORED or on memory for max adapt. He said with those codes, the car seemed to still run excellent. I asked if one of those codes can cause transmission whine and he said not really. And he mentioned a code and said that the PCM detects the transmission is taking longer to shift and it sets the code, but this wouldn't cause whining. He also said to bring it back if the whining comes back and they'll drive it for a few hours and see if anything happens. He was moving the shifter around to feel how the transmission shifts into each gear and he said he couldn't feel nothing wrong. He said something might be clogging the filter and they could just drop the pan and see if there's anything inside. He said to come back when it whines, so when I left the shop, I drove 4 blocks away, and the whining started! I was in heavy traffic so I didn't bother turning around. I also took the car to auto zone to have it scanned and the only code they got was for the MAP sensor. I guess you need a scanner tool for the transmission?
Anyways, I researched online about max adapt, and I heard it's a extremely common problem in GM vehicles. And my car seems to fit the symptom of the whining part that disappears once you turn the key on and off, but it doesn't seem to shift hard when this whining occurs.
Sorry for writing all this. I can't really afford a transmission rebuild right now. Do you know what transmission I have? Also, are the transgo kits any good? The mileage odometer reads 197k but runs really well. I wish I would've researched about the transmissions before I bought the car!
The price I got it at and the condition it's in, is really good in my opinion. I just didn't think there would be a transmission problem because I test drove it for a while before buying.
EDIT: The whining seems to appear on hot days, like 80-95 degrees fahrenheit. The night that I drove it for 90 minutes straight when the whine didn't appear, it was about 64 out, so it was much cooler.
