I have a 3.1 which until about 3 months ago, never made any strange noises. Then it started. When I accelerate, I get a noise that sounds something like fluid that is frothing (if you can imagine frothing fluid). It sounds like liquid that is foaming very, very rapidly. There's no bubbling sound, and no grinding like a metallic sound would make. The engine doesn't seem to run any differently - the tranny shifts good, the engine doesn't miss, etc. But the noise has gotten louder with time. After accelerating the noise tends to die, but will reoccur if I give it the gas. It only seems to happen when I apply the gas - the more gas, the louder the noise. The noise seems to originate close to the firewall - actually it almost sounds likes it's under the dash on the left side. It's not as noticeable on the right side. It has me stumped. I've driven about 1 1/2 million miles and never seen this before. This lumina has 99K on it.

That sound is kinda typical of a vucuum operated switch that is leaking, they will make a kind of gurgling, hollow sound like when you suck the last drops of soda outta a cup though a straw. Is that what it sounds like?

Just thinking, A/C systems are known for that kind of sound also, you could be hearing something occuring in the evaporator area of the system. Does it do it with the air off or on?

I thought it might be something related to the heater core, but it doesn't seem to be in that area. I've had heater cores make funny noises, but not the same as this. The evaporator A/C issue might be possible, but the location of the noise seems odd.

Doesn't really sound like sucking the straw thing. It's almost like pushing air through a straw into a liquid and creating a million bubbles, but without the obvious bubbling sound you usually associate with blowing air through a liquid. The vacuum problem might be a possibility, but it doesn't have the sucking sound I usually associate with vacuum leaks. It's almost the opposite, as though something is being pushed out. And it doesn't sound like air - it's more liquid sounding.

I know this probably doesn't make much sense. But it's hard to describe, especially since I've never experienced this before.

I thought it might be something related to the heater core, but it doesn't seem to be in that area. I've had heater cores make funny noises, but not the same as this. The evaporator A/C issue might be possible, but the location of the noise seems odd.

Doesn't really sound like sucking the straw thing. It's almost like pushing air through a straw into a liquid and creating a million bubbles, but without the obvious bubbling sound you usually associate with blowing air through a liquid. The vacuum problem might be a possibility, but it doesn't have the sucking sound I usually associate with vacuum leaks. It's almost the opposite, as though something is being pushed out. And it doesn't sound like air - it's more liquid sounding.

I know this probably doesn't make much sense. But it's hard to describe, especially since I've never experienced this before.


The vacuum module on the Ford parking brake release was known to cause exactly this kind of sound when leaking. Odd thing is, a vacuum leak will increase in intensity as the throttle closes, being heard best at idle. So yeah, I doubt its' that, now that I think about it. Does it do it if the motor is revved in park, without vehicle movement? That could be telling.

Just went out in the rain (you're welcome) to look at my '97's engine compartment. Two things jumped out at me. First, check your brake fluid, hopefully you are not hearing small amount of brake fluid being sucked into the booster through a bad seal. And the A/C evaporator core and expansion valve are right below the driver's windshield wiper, on the firewall. I'm begiinning to think this is where your problem is. The small bubble analogy jives with what actually occurs in the A/C system.

Hey, Jeff

Thanks for all your help and insights. I think I may have found the problem, but I've never seen this before.

My tranny fluid was low, so I added some and brought it up to the desired level. When I did that, almost all the noise subsided. I still have a little of the same noise - when I make sharp turns and accelerate suddently at the same time. But most of the noise is gone.

The funny thing is that the tranny didn't slip the whole time - the first sign the fluid is low. I had changed fluid and put in a new filter about 25K ago, and I checked the fluid level when the noise first started a couple of months ago. But the fluid wasn't that low. Today I checked and the fluid was lower, so I added some.

I still haven't figured out why the noise on sudden turns with acceleration. But I'll keep at it. Funny thing, also. When I rode on the passenger side, the noise wasn't nearly as loud. Seems to be louder on the driver side, but the tranny seems to be the culprit even so. At least, that's how it's looking now.

In all the years I've driven I've never seen this one before. Maybe it comes with having a Lumina.

That is intersesting. Someone else here mentioned a "swooshing" sound that they attributed to the tranny before it went bad. Hopefully, that's not the case here. I just changed the fluid and filter on the '97, and refilled with 4.5 qts to start, and the level was low. I drove to the parts store after adding the .5 I still had, it shifted perfect. Bought 2 more, and ran 20 miles on the highway to get everything filled/circulated/heated. Was shocked that it was still 2 qts low at this point! No noises, and no problems shifting at 2 qts low. Unusual in my experience, but may be typical for these. Total after all said and done-7 qts. Most GM FWD that I had worked on in the shop took about 4.5-5 qts and that was it. I noticed this one is a little different design than the GM's I worked on routinely. (I had a '77 Ford LTD with an FMX trans-took 14 qts to change the fluid!! That car was built better and more heavy-duty than most trucks today)

You point out a very good piece of advice, that I sometimes forget to mention, not realizing that everyone is not a mechanic. Always start with the basics. Fluid levels, visual check, electrical connections. Half the time you will find the problem somewhere you would have never thought. And by not verifing the basics, you can be in for a lot of tail-chasing. And second, check that any recent work done is not the problem. I had a rule in the shop. When a customer said "It can't be (name of part or service), because I just had it done", usually they just told you what the problem IS. Seeya!

Just went out in the rain (you're welcome) to look at my '97's engine compartment. Two things jumped out at me. First, check your brake fluid, hopefully you are not hearing small amount of brake fluid being sucked into the booster through a bad seal. And the A/C evaporator core and expansion valve are right below the driver's windshield wiper, on the firewall. I'm begiinning to think this is where your problem is. The small bubble analogy jives with what actually occurs in the A/C system.


Alert! Alert! something just flashed into my head. Your trans filter may not be fully seated and is now sucking air. That would produce the sound you mentioned, if the pump is trying to pump aerated fluid. Please check into this!! You may ruin the tranny if this is the case!

Hey, Jeff



I still haven't figured out why the noise on sudden turns with acceleration. But I'll keep at it. Funny thing, also. When I rode on the passenger side, the noise wasn't nearly as loud. Seems to be louder on the driver side, but the tranny seems to be the culprit even so. At least, that's how it's looking now.

In all the years I've driven I've never seen this one before. Maybe it comes with having a Lumina.


The fill tube runs up the driver's side. The tube can act and a conduit and resonator for tranny internal sounds. The trans case is on the driver's side. The filters on these are a press fit, and if not fully seated, can drop down and cause the filter(essentially a pick-up too)to suck air, aerating the fluid. This causes poor lubrication internally and overheats the fluid. Aeration in the pan can cause the pickup to run dry when the vehicle is turning or accelerating. Have seen some that would actually slip outta gear taking a corner, because of this. I may be wrong, but if not, you are on the way to buying a new tranny if you ignore it!

Jeff,

How interesting someone mentioned the filter being off as a possible cause. I had initially considered that as a potential problem, but never having had that happen before, I wasn't sure what kind of noise it would make. But I did wonder if the filter had come off. I put the filter on about 25K ago when I changed fluid, but as mentioned, the fit on these trannys is iffy at best. I will need to check this asap I guess.