I have an old Buick I use as a daily driver. It's an '88 Park Ave, FWD 3.8 V6, 4 speed auto. It's made an odd noise on the way in to work this morning that I can't pin point. The noise sounds like a VERY bad PS pump, you know the whine I'm talking about. It's not the PS pump, I can hear it as well as the noise in question at the same time on occasion. The noise only happens when the car is moving. The noise stops when the car comes to a COMPLETE stop, at a 1-2 MPH roll, it's still there. Also, it seems worst rolling in a straight line. Turning seems to make the noise go away, at least momentarily but not always. The noise seems to get louder the slower the goes but does not seem to change pitch with speed. The brake pedal does not affect the noise, it's the same on or off the brakes.

The front brakes were new a couple months ago and I replaced the right half shaft about 4 months ago. PS pump and harmonic balance were replaced at the same time as the half shaft. Everything else looked fine at the time I worked on it.

Since I'm in the office all day and can't go look at it until this evening, I'm stuck speculating. If you're anyting like me, you know how much it will bug me until I figure out what it is. I'm a bit stumped. Any ideas?

So it is speed related? Start with the obvious, hubs,shafts, make sure something is not hitting anywhere. It could be a problem with the tranny. Do a quick,safe lane change on your way home go both left and right. If the noise changes tone its one or both hubs.

If it is just engine speed related remove the belt and spin your accessories until you find the problem.

If you do not find anything start it up and see if the noise is there. Keep an eye on your guages of course. Possible timing chain if the noise is there.

I was thinking possibly front hub/bearings myself. But I would think the noise would change with speed if that were it. I wish I could watch gauges, but I don't have any. This is one of the old GM's with nothing but idiot lights. Speedo and fuel level is all I get.

I don't think it's an engine or accessory noise. The noise stops when the car stops whether the engine is still running or not.

I suppose tranny or torque converter is a possibility. But would that noise stop when the wheels stop turning but the engine is still running?

About the only time I don't hear the noise is when the car is moving at 35+ MPH. It may still be there, just can't hear it over everything else. Thinking more about it, it didn't do it when I left the house this morning and I didn't hear it until I got off the highway near the office. Could it be heat related as well?

Just went down and checked the fluid levels. Tranny, PS and engine oil are all full and clean looking. Shook the wheels (car on the ground) and see nothing. No appearent leaks. Started in in the parking spot (to check tranny) and no noise. I'm really getting stumped on this one.

I'd be looking at that other half-shaft, or boots. Can you support the front end on jackstands with the front wheels off the ground and still make the sound? Maybe something to try. If so, make sure someone's behind the wheel when you test, just in case.

Hmm. I think I would need a test drive to help any further, but Colorado is a little far. I would try what Gene and I have suggested when you get home. It should narrow down the possibilties. Besides it a good opportunity to check out all the steering and suspension while you have it in the air. And I am not sure but doesn't that tranny have a drive chain? That was what I was thinking when I said possible tranny problem

I have no clue if there is a chain in that tranny or not. I'll definately be doing so more in depth investigation this evening. Thanks for the help.

I believe they do, but that ties the flywheel to the torque converter. They tend to pop and rattle when they get old, but if they squeaked or buzzed, it would be in sync with the engine. The noise in question seems to be in sync with the car's speed, IIRC.

Wouldn't you know it? The day I need to work on the car and we get a mini blizzard just before the drive home. The investigation may have to wait.

I had an 89 LeSabre beater so I'm familiar with the drivetrain setup. I'd say its either the wheel bearings or the trans. I replaced both wheel bearings while I had mine. I also had a torque converter go bad on the 440T4 trans (might be referenced as a 4T60). I had similar issues with my 91 Grand Prix (same trans/wheel bearings). With the wheel bearings, it definitely changed pitch as you turned/changed lanes. With the torque convertors, they both drove fine, just made noises at idle in drive or park. That doesn't sound like your issue. I know that those transmissions had a number of other issues. I got rid of the LeSabre when the trans died (190K miles) if thats any indication.

The mystery continues. With the short but nasty little storm that rolled through yesterday afternoon, I didn't get to look at it. Took 1.5 hours to get home and the car was a sloppy mess. The noise did not reoccur on the way home or on the way in this morning. I'm certain what ever it was still needs to be fixed, but apparently, it's going to let me wait until the weekend to look at it.

All that snowmelt leaking into the front wheel bearing kept it lubbed up! :-D

The 440-T4 has a drive chain and Torrington bearings that are notorious for that type of noise. I would want to drive it before I condemmed it, or you you try to record the noise and send me the file. Wheel bearings will start as soon as the car moves, and I have seen situations where they only make noise in a straight line. Wish you were closer........

Because it ONLY made noise with the car in motion, I'm going to begin the investigation at the front wheels. I sure hope it's not in the tranny. I can't afford to replace this thing right now or put a tranny in it.

that's where I would start as well...... let me know if I can help.........

What about in reverse... is the noise still there?

The mystery deepens.

Reverse? Don't know, never tried. In driving it a bit more, the noise only seemes to happen after the car is fully warmed up and been driven for a while. I got the front wheels off this afternoon. I found NOTHING wrong. The bearings are good, the brakes look good, nothing seemed out of the ordinary at all. I removed both hubs just make sure, both rolled very smooth and with no play. I also checked for play with the tires on, nothing. I cleaned it all up, regreased the caliper pins and put it back together. I guess I'll find out tomorrow after I drive it a ways and see if the noise is still there.

Did you get it fixed?

It would seem to be fixed, the noise did not occur today. What did I do to fix it? I don't know. I replaced NO parts. All I did was disassemble, clean, inspect and reassemble. Apparently, that's what it needed. In some ways I'm happy it didn't cost me anything but time, in other ways I just waiting for it to return because I don't really believe it's fixed.

I know what you mean. I hope it stays fixed