Possible transmission issue

I recently purchased a 2000 Sunfire 2.2 with automatic transmission. I’ve been slowly working on repairs for it, brakes, new cooling fan and know it needs a new wheel bearing soon but I also am experiencing a humming noise from around the engine when I accelerate and even in park when I hit the gas. The car shifts smoothly, the rpms do not rev before it shifts but you can noticeably feel the shift from first to second and to third. It never fails to shift at the same times, just feel it shifting, so not smooth in that sense. The car doesn’t hesitate, no issues getting up to speed or going into any gear but sometimes it doesn’t want to go into park unless I shift back to neutral and then into park. Any ideas? Thanks!!

If you are hearing that noise when the trans is in “park”, then I think that you can rule out the transmission as the source of the noise. Instead, I would suggest that you focus on the engine, particularly things such as the belt pulleys. After 15 years, it is certainly possible that you have dry bearings in one or more of those pulleys. It is even possible that the alternator is the source of the noise.

That being said, unless you know for sure that the transmission was properly serviced by the previous owner(s), I strongly recommend a fluid and filter change a.s.a.p., in order to extend the life of the trans.

first step I’d take is to change the transmission fluid and filter…if it has one.
I change mine at 30,000 on my work truck and 50,000 on the wife’s mini van.

I always take the position that none of the regular maintenance has been done on a used car purchase.
I always change the oil and filter, tranny fluid and filter, flush the brake lines, and replace the coolant and a new thermostat and hoses, and new belts.
I never believe the seller on maintenance items.


Since your car is now 15 years old, it is a teenager. Teenagers whine, they don’t hum!

Kidding aside, transmissions generally don’t “hum” they whine. The hydraulic pump in the trans is turned by the engine whenever the engine is running no matter if the tranny is in park or not. Pump problems usually start with a whine and just get louder. Agree with the others, change the filter and fluid and look elsewhere.

Pulleys or alternator are good places to start.

The humming sound is probably unrelated to the transmission. Since you can hear it when parked, a mechanic could likely use a car-stethoscope to identify where in the engine compartment exactly it is coming from.

For the abrupt shifting, I concur w/the advice above, get a proper transmission service done first. If that does’t fix it, it is probably just from normal wear. Automatic transmissions have clutches inside that wear a little with every shift, and abrupt shifting is one of the symptoms that can indicate they are nearing the end of their useable life.

Thanks for the advice guys, I will look into those things! Now to figure out cost lol

The last whine that I got from an engine turned out to be the alternator with a bad rear bearing. It’s easily checked with a stethoscope or a 3ft piece of rubber hose.