I own a 95 Saturn SL1 with 170,000 miles on it. It has been reliable, basic transportation for years. The manual transmission recently began making a high pitch whirring noise (like a dentist’s drill) at low speeds, which I asked my mechanic about when the oil was being changed. I had asked him whether I might have clutch problems, because the last time I heard such a sound was when I suddenly had to replace the clutch 25,000 miles ago. The mechanic said it was not the clutch, just an old transmission starting to make noise, there was plenty of fluid in the transmission, and was not worth worrying about. I have two questions: (1) is don’t worry, be happy the correct approach, as my mechnaic seemed to imply; and (2) is it worth being proactive (and how much might it cost) to take the car to a specialized shop somewhere to get the transmission rebuilt, etc.? Don’t think the car will last forever, but I typically drive only 5,000-10,000 miles per year and so in a perfect world would like to keep the car another 2-3 years (call me thrifty, but I do not see the point of either buying a fast depreciating new car, or taking a chance on a used car). Who has a technically informed opinion on the proper response to the transmission noise?
You might take it by a transmission shop; have the technician listen to the sound; and give his opinion. A transmission lubricant oil change might be a precautionary measure to see if there is any debris and to get that out of there.
A transmission rebuild at this time would probably not be cost effective. You might just drive it until the problem becomes critical then have a used transmission installed. If the sound does not appear in 4th and 5th, I would not be concerned about driving it on the highway and its reliability. Otherwise, a wait and see approach might be best.
The only thing that I disagree with Researcher on is taking it to a transmission shop. I don’t even know of any shops that specialize in manual transmissions. What ever you do, don’t take it to a chain transmission place ie. aamco. If this is happening in first gear, great. I might worry more if it was in high gear, but not much even then. I am with Researcher, drive it and keep an ear on it. If it gets worse, sounding like someone is mixing a bucket of bolts in there, you might worry about it. Changing the fluid and looking to see if there are any big chunks in there might be prudent and will be cheap is a good idea. If at any time your trans gives up, slavaged trans from a wreck would be the best way in a car this old. Try to find a salvage yard that does installation. If they put in a bad one, they have all the responsibility. That is especially true if later models have the same trans and you can get a lower mileage unit.
That whirring can come from a lot of things, a bearing, a bent gear tooth, a bent shifter fork… It might even be a prematurely failing clutch as your experienced ear is telling you. If it is not the clutch, in low gear you might not be using that particular part much so it could last you another 100K. Something else in the trans could wear out sooner. OTOH, your engine could fall out sooner or someone might steal the car sooner. It is time to relax and enjoy the liberation of driving an almost worthless vehicle.