Question regarding rattle in '94 Cutlass Ciera S 3.1V6

[Ardan]

As the topic says, I have a 94 Cutlass Ciera S, 3.1L VIN M. It just rolled over to 130,000 miles a few days ago, but we've done a bit of work on it. We've replaced a bunch of sensors over the last 4 or 5 years, and it recently needed new shocks and struts, so we replaced the ball joints and put new brake pads on while we were doing the rest. About 9 months ago, the transmission had lots of trouble in 2nd gear and decided it didn't want to go into 4th gear, so we had it serviced. Actually, we removed the transmission ourselves and they did all the work on it, but we reinstalled it ourselves. In 2002, I guess we had a problem with the clutches in the transmission, so a rebuilt was installed by that company, which is a very well-known and respected company. They said last year that there were clear problems with that rebuild, and if we have any problems, we should take it back and they will check things out for free.

That being said, I drove back home from the grocery store (a short distance) and I noticed a rattling sound from the engine compartment. There's a scraping sound that comes from the A/C area when it is off, but that is a different sound and I already know that it is harmless. However, this is clearly some sort of rattling noise. It went away in park, so I flipped it back to Drive, then to reverse and I heard the noise again in each case. It was 10:45pm and I was tired, so I didn't do anything else.

I have the entire day off on Monday, so I thought I would check and see what you guys thought. When I changed gears, it changed them instantly and didn't seem to clunk loudly or anything like that. When driving home, it didn't feel like it was having troubles shifting or getting started. It idled very well, and it shifted gears smoothly. Sorry I do not have any more detail, but I wanted to quickly whip up a message. Does anyone have an idea on what it might be? I figure I should check the oil before I do anything tomorrow, and then if that is okay I should warm up the car and check the transmission fluid as well. Do you think I should also have them inspect it?

If someone has heard a similar sound, then by all means share it! I am open to any suggestions. I definitely better take any weird noise seriously if its going to last me until I buy a new car. I've been stashing money away in a separate savings account for it with the hopes of buying one next year or the year after that, since it has been running so well for a very long time. Other than the transmission, it has only needed new sensors. Before 2002, it had absolutely no problems of any kind. Overall, it has been very good!