1998 GM LS 130k

I hear a groan/hum when accelerating and decelerating. The noise appears around 15mph and is loudest around 50mph. Its gets quieter at higher speeds and i dont hear anything when cruising on the highway at 80. It also changes pitch with changes in speed or when I give the car gas and put torque on the driveline when cruising above 15mph. Its also present when decelerating and cruising to a stop. I cannot locate the noise. Anywhere between the trans and rear of car, but im thinking it located around the trans. Its not present when idling or reving engine.

i also get a clunk when shifting into reverse. Not sure if this is related. Cars runs great. Any ideas? Thanks!

 

Hi, did you figure your noise out? My '00 is doing the same thing. When I first noticed this I checked my axle fluid which was low and discovered driverside axle seal was leaking. Replaced that and still hear a hum. I'm starting to hear a clunk when putting it in reverse. That's normally the U-Joints going bad. That will be my next project to look into and hope this is also causing the humming noise.

 

This is one of the most frequent problems with oil, because the real oil is not very good, that's why the engine starts buzzing. It happens especially often when someone is going to save on it. You can't do that, and you have to try to pick up the oil for a particular engine of a particular car. I didn't know it from the beginning when I first bought a car, and that was a year ago. Because of course I had problems, I also had a terrible buzz. It's good that at least then I picked up here for my honda civic oil type https://carfluidsexpert.com/best-oil-for-honda-civic/ , which is perfect for it. So the rumble stopped and recently I was driving at a service station and I was told that the engine was normal and in excellent condition. I usually take the AmazonBasics 0W-20 Full Synthetic Motor Oil, but you can pick up another one. Here you can already see and look at the article that I threw above and see which priorities are most important to you. I had no problem finding the right one and I think you can do it too. Then there's a chance that this whole rumble will disappear, just like it happened to me.