A couple of months ago, while I was driving my 1994 Pathfinder slowly in a parking lot, I noticed a strange noise coming from the engine area. It was a soft, high-pitched sound that seemed to be independent of the speed of the car. It stopped after a few seconds.
I've heard this same noise just a few times since then, but yesterday I heard a more ominous noise that may be related to the original one. It was very cold here (near zero including wind chill), and shortly after starting the Pathfinder I was driving it up a hill, in overdrive.
I noticed that the power was quite poor, and a few seconds later I heard a groaning noise that was much louder than the original noise I heard. The noise again seemed to be independent of the movement of the car. Also, as a test when I was stopped at a light, I shifted the car into neutral and I do not believe that had an effect on the noise.
While I was stopped at the light, the groaning sound began to "wind down" somewhat like an airplane engine. Then the noise stopped with a soft bump and all was normal with respect to engine strength. Drove the car on a 50-mile trip after that and it was fine.
i hate to bring cars into shops with vague descriptions, as that can lead to an expensive fishing expedition, so any leads you can give me would be greatly appreciated. Does this sound like a bad torque converter? Timing chain?
(I should tell you that we had the transmission replaced a few years ago after a shop misdiagnosed a fluid leak. They told us we had an oil leak when it was transmission fluid, and the transmission soon locked up and had to be replaced.)
Thanks, Al