Alright, I know these questions usually start out with not enough info and usually draw tons more questions in response, so let me try to be as complete as possible with what I know so far. So appologies in advance for being so long. Also I have searched all the other posts regarding trans noise and none seem to have been the same problem so far, so I am posting with that in mind. Here goes:
I purchased this 2001 GP GT about 5 months ago. It had 131,000 miles on it. When I bought it it was just starting to exhibit the classic intake gasket leak, so I replaced the upper and lowers and did a coolant flush, and at the same time I cleaned the engine (externally) with Gumout Steam Clean in a can. I cleaned the engine before I did the intake, and again after it was complete. Very soon after completeing this repair, I started to notice an intermittent whine, like a pump noise. At first I figured I cleaned some gunk off something that really missed it while cleaning the engine. As the noise started to become more frequent and pronounced, I guessed that it was the power steering pump. I based it on the type of pump squeal type sound that I was hearing, and a test that I did where when it was making the noise I turned the wheel lock to lock, and the squeal stopped momentarily until I released the wheel. It did this repeatedly about 4 or 5 times, and each time I hit the lock, the squeal would stop. So I replaced the pump and flushed the power steering fluid. The squeal was unchanged.
After thinking about it, I had a hunch that maybe it was the transmission. I started to also notice a very faint slip at very low throttle, less than 7 or 8% according to the TPS. I did a trans flush (including using seafoam just before the flush), dropped the pan and installed a new filter and gasket, and installed an auxillery trans cooler. The trans fluid needed a flush anyways, so that part was just PM. And the trans cooler was just a good idea as it seemed to run hot to me. Usually the same as the engine or a few degrees hotter before the cooler. Now after the cooler it runs at least 15 degrees cooler than the engine, and usually about 30-40 degrees cooler. This allowed me to make a new observation, the squeal only happens when the trans fluid gets warm, around 130-140 degrees from what I have observed. It does not squeal on a cold start when the car has been sitting all night. Turning the car off and restarting it has no effect as long as the fluid is still warm. It will squeal in any gear, even Neutral or Park. It is the same noise while driving too, although it gets harder to hear while driving because of wind and road noise. It dosent really get louder with engine RPM, but it does change tone slightly, like you would expect a pump squeal to I guess. It seems to quiet itself when the engine is completely at idle, but as soon as you nudge the gas the slightest bit it starts to squeal again. If the trans fluid is too hot, say up to 180-190 degrees it is less likely to stop squealing at idle, or take longer at idle to quiet down. This is an improvement over what it was doing before the flush, which was squealing non-stop regardless of idle or not, but I think that may be becuase the trans is running cooler now, not becuase of the fluid, although it may be a bit of both, not sure. Also that faint slip at low throttle has improved, and I have not noticed it since the flush. I did the flush about 300 miles ago. The car now has around 134500 miles. The car runs and drives and shifts perfectly now, and if not for the noise would have no other issues.
So what are your thoughts, could this be an oil pump? Could it be another trans component? I am not 100% sure it is the trans making the noise, but the corrolations with trans temp seem to point to that. Any help in further testing or isolating the noise, or opinions on what the noise is would be greatly appreciated.
Thanks In Advance!