Transmission Whine?

2007 Chevrolet Impala 1LT (purchased Nov 2006)
3.6L V-6 Engine
Automatic Transmission
32,000 miles (yes, low mileage)
Original owner. All book maintenance maintained on schedule.
Transmission fluid at proper level and still clear pinkish color.

Recent history: Several months ago was having major trouble shifting out of park gear due to torque lock. Mechanic unable to duplicate problem at shop so lubricated linkages which greatly lessened but has not cured torque lock problems.

Power train warranty expires 2 months.

NEW/CURRENT PROBLEM:

• Has developed loud whine similiar to how power steering low on fluid sounds but is NOT the steering whining.

• No whine if foot off gas, even if turning the steering wheel hard, so am sure it is not the power steering that is whining.

• Whine is heard ONLY when gas pedal is depressed and especially loud when car is in low gear starting up from a stop or when accelerating uphill. If I take my foot off the gas pedal and coast, the whine stops.

• Pitch and loudness of whine goes up when engine RPMs go higher; pitch and loudness go down when RPMs go down.

• No change in average gas mileage, no stalling, no hesitation such as gas feed might produce.

• Transmission is doing very slightly more “hunting” for gear than normal when going uphill in slow city traffic, although has always tended to have this problem.

Plan to take the car to mechanic soon as they have an appointment opening. Was planning to have regular transmission service with change the tranny fluid and filter soon anyway, although book doesn’t call for it until 50,000 miles. But since the car is 5 years old and gets mostly short trip stop and go driving think it best to do tranny service early, especially with the warranty about to expire.

Any ideas if this really is the transmission whining or other possible cause of the whine?

Thank you.

Marnet
…still reading, still learning…

I would absolutely take this to a local, dedicated transmission shop and have it scanned. The 4T65E transmissions are widely loved when they work but are also very trouble prone regardless of actual mileage.

It is not necessarily the case that the whine is the transmission, but if it is then what it means is that the PCM has the line pressure ramped up for some reason. It does this when it has detected a problem. So if it is transmission pump whine then a professional scan should pick it up. Do this even if the check engine light is off. GM, in its infinite wisdom, has decided to program things so that many, many error codes can be present without turning on the MIL. Many of those will relate to transmission issues.

Do this immediately and keep documents so that you get it checked out before the warranty runs out.

Are you using the parking brake? Not using it can cause it to be difficult to shift out of park, especially on an incline.

But I don’t think that is related to the whine. That sounds like a bearing inside the transmission. Is the whine pitch dependent on engine rpm’s or vehicle speed? If the whine pitch goes down on each upshift, then it would be on the input side of the transmission.

How loud is the whine. My Saturn has had a slight whine since about 30k miles. It now has about 237k miles and the whine has not gotten any worse, that I can tell anyway. My HF hearing has gotten worse so maybe I just can’t hear it as well, but no one who has ridden with me has complained about it.

Not sure how long there was a low whine because I usually have the radio on but had heard it last week when I had the radio off. Over the weekend it has become very much louder such I can hear it over the radio.

To answer your question, yes, the pitch goes down with each upshift then gradually rises in pitch again until the next upshift. The pitch and volume of the whine rises and falls with the rise and fall of the engine RPMs.

There are and have been no warning lights, no check engine light on in the instrument panel. If there is an error code it isn’t triggering the idiot warning light.

Thank you for feedback.

The “idiot warning light” is only required to be triggered by codes that affect emissions. The rest of the codes can remain hidden. Not all code readers will read these “manufacturers codes” so going to AutoZone,etc. isn’t going to help.

Thank you. I’ve an appointment to take the car day after tomorrow, so guess I’ll find out the good or bad news then.

Sounds like it may be the torque converter, sometimes they whine before they let go. Usually when the TC lets go, you get small bits of metal in the fluid, which means it will take the rest of the trans with it.

Oh, that sounds simply charming. muttering and grumbling

One correction to info: it has the 3.6L Flex Fuel Engine. Don’t know if having the Flex Fuel version makes a difference.

Do this first if you have not done so already. Remove the serpentine belt and start up the engine to see whether the whining stops. I distinctly remember back then GM having issues with the serpentine idlers going bad. Not positive on your engine but it should have a tension pulley AND an idler pulley. One of these could be the culprit. Doing this will rule out the engine components. One thing I have learned over the years is check the easy stuff first. Dont go jumping the gun and start tearing the trans down because you can be in for a big let down after all that work and the whining continues the first time you crank her up.

transman

Thank you Transman.

I have an appointment for tomorrow morning to take the car in. I’ll mention your advice when I do.

Due to physical limitations, I’m not able to perform any of my own maintenance. But I VERY much appreciate getting professional advice and feedback so that I’m less ignorant when I drive through the door of the mechanic’s shop.

Here is what I’ve printed out for the mechanic to see at this morning’s appointment in a few minutes. I’ll post later what the shop does or does not find about these problems. Note: the problem with the screeching parking brake developed since I first started this thread.

Printout reads:

Problem 1

• Has developed loud whine similiar to how power steering low on fluid sounds but does not seem the steering whining. No whine if foot off gas, even if turning the steering wheel hard.

• Whine occurs only when the car is in motion and only when I’m applying pressure on the gas pedal. If I lift my foot off the gas and let the car coast the whine stops. This is true whether on a level stretch of road, headed uphill or headed downhill. The whine is loudest when there is the most pull on the engine such as heading uphill from a stop light. The whine is less if the engine is working less. So maintaining speed on a level causes minimal whine. But accelerating at any speed increases the whine. The pitch of the whine goes higher along with the sound volume of the whine increasing as engine RPMs increase. When a shift point is reached and RPMs drop the loudness and pitch of the whine drop.

*Whine not heard when engine is cold. Whine only heard once engine is warmed up.

• No change in average gas mileage, no stalling, no hesitation such as gas feed might produce.

• Whine has begun in past couple weeks since I happened to lightly wash off the engine with a garden hose spray. No hard water pressure or soap used. Hood left open for engine to dry well afterwards. No clue if there is a connection or mere coincidence.

Problem 2

• When car is parked on an incline, front end downhill, once the car is shifted into park gear, the parking brake set, engine turned off, and foot removed from the regular brake pedal, when the car rolls forward some there is a loud groaning metal-on-metal screech. Cannot duplicate if parked on level, parked with front end uphill, or if parked without the parking brake applied.

Problem 3

• Still experiencing occasional torque lock making it difficult to shift out of park into reverse or drive. Happens mostly when the parking brake has been applied while in park. Happens whether parking brake released before or after attempt is made to shift out of park into reverse or drive.

Several months ago was having major trouble shifting out of park gear due to torque lock. Mechanic unable to duplicate problem at shop so lubricated linkages which lessened but has not cured torque lock problems.

re. problem 2:
With drum brakes in the back or disks with a small drum parking brake
the backing plate or some other part of the mechanism may just need lubrication.

UPDATE:
Turns out it was the power steering. I thought it couldn’t be because of how and when I heard the whine. My error.

To quote from the service printout:
“Checked fluid and found to be low. Inspection found fluid leaking from LH side of rack at boot. Replaced power steering gear assembly and reset toe as required. Auth 90A goodwill warranty assistance due to mileage and product durability concern.”

I am profoundly grateful that GM chose to cover this under goodwill warranty. I’m writing a letter to the dealership management lauding the exemplary customer service efforts of the service advisor who made the effort to get the issue covered under warranty despite it being almost two years past warranty expiration (although still far short of normal mileage.)

In regards to the metal on metal screech of the parking brake, again to quote from the service printout:
“Parking brake pedal has no resistance. Seems to hold on inclines. Removed rear calipers and rotors to clean and inspect parking brakes. Adjusted parking brake shoes and cable as needed.”

So now rather than having the parking brake pedal easily go all the way to the floor it takes considerable pressure to depress it just an inch or so. Huge difference.

So, I was grossly in error thinking it couldn’t be the power steering whining because it did so only when the throttle was engaged but not when the engine was coasting. Also, I had found no trace of leaked fluids on the garage floor despite checking several times in the past week. Apparently the leak was such it was drying on the boot and not making it to the ground inside my garage.

I ended up paying only for the parking brake work. Very fair treatment.

As my dad used to say, not all education comes out of a text book. And I’ve had my education added to in this case.

Thank you very kindly to each and every one of you who took the time to read and respond with your advice. I highly appreciate the assistance in helping me learn more about how to properly maintain my car so I get long use from it.

Oh good, glad it was something simple and didnt cost you anything but some time.

transman

“Inspection found fluid leaking from LH side of rack at boot.”

“Also, I had found no trace of leaked fluids on the garage floor despite checking several times in the past week. Apparently the leak was such it was drying on the boot and not making it to the ground inside my garage.”

Marnet, first let me compliment you on your great descriptions of car problems and also your automotive savvy. Based on the diagnoses that were made here, I think everybody with an open mind learned from your experience.

Your car has two “boots” (hollow accordian rubber sleeves), one on the right end and one on the left end of the power steering rack. The purpose of the boots is to keep dust, debris, and moisture from getting to the seals on the rack ends. The contamination would cause the seals to wear. The boots are accordian-like to allow movement of the inner tie-rods, so they can steer your wheels when you turn the steering wheel, and yet still keep the contaminants out.

However, sometimes steering rack seals fail and develop leaks without being exposed to any contamination. When that happens the leaking power steering fluid would be seen on the ground, but . . .

. . . the boots will inadvertently ( It’s not their job, man ! ) hold the fluid inside so that it can’t drip on the ground and will not be seen or noticed unless somebody checks inside them.

That’s probably why it was leaking and you did not see it. A check of the fluid level in power steering reservoir (has a sight window or dipstick) would probably have alerted somebody that the fluid was leaking somewhere, and if not on the ground, then pobably within the boots.

“* Has developed loud whine similiar to how power steering low on fluid sounds but does not seem the steering whining.”

“Checked fluid and found to be low. Inspection found fluid leaking from LH side of rack at boot.”

These things almost always seem to make much more sense in retrospect. Marnet, Thanks for sharing the experience. I’ve learned from it.

Regards,
CSA (We love the 2 Impalas in our family.)

Thank you CSA for the compliment but especially for the explanation of the construction of the power steering system and why I wasn’t seeing any leaked fluids on the garage floor.

As much as I respected and still respect my late father, he was not at all savvy about anything mechanical (the joke in the family was that he could fix things beyond repair!) and therefore in the past I was not at all savvy about car maintenance and repairs.

About 6 to 7 years ago, I began asking questions here about my then aging '87 Olds in hopes of solving some chronic problems. That morphed into my asking many questions that helped me shop for a new car. And I’ve continued to ask questions about the few issues I’ve had with the Impala in the five years I’ve had it.

By periodically taking the time to read many threads here on the forum, even when I have no questions of my own, I’ve learned a GREAT deal about how better to maintain my vehicle and how to know better what is going on when I take the car in for routine maintenance and/or repair of any problems. Given my physical limitations I will never be doing any of the work on the car myself. But it is extremely helpful to understand as much as I can so that I’m a reasonably informed owner. That said, I’m as capable as anyone of significant lapses of judgment, misunderstanding, or clinging to outdated and no longer applicable ideas about cars. It wasn’t easy to shift from believing my dad’s approach was gospel to accepting that at least some of his notions were outdated or downright erroneous.

I’ve often said this before but will repeat that I am quite grateful to all of you forum regulars who take the time and effort to share your knowledge, experience and expertise so that those of us who are not mechanically knowlegable may benefit. All of you are providing a real and valuable public service. Yes, I know y’all enjoy doing so but still it is kind and generous of you to do so.

Regarding this specific issue of the power steering whine, it has been quite a learning experience for me also. My first suspicion was power steering because it had that distinctive sound. But when I paid close attention to when I heard the whine and made a point of test driving a variety of conditions I quickly assumed it could not be the power steering based on the fact I only heard the whine when pressure was applied to the gas pedal and not when I let the engine coast. The whine seemed to be tied to engine RPMs. And since I had had a problem with torque lock recently, I jumped to the conclusion it could be the transmission. It was a very logical progression in assumptions, all of which proved to be wrong wrong wrong except for my very first thought that it sounded like power steering low on fluid. Lesson learned, even while considering additional possibilities do not discount one’s initial suspicion.

I am still puzzled why the whine did not occur when the engine was coasting, even if I made a hard turn??? I’m assuming that had I not had this looked at and fixed early it would have become a significant problem and would have been a constant whine along with difficult steering. But why didn’t it whine for all steering and just when the gas pedal was depressed???

See, still asking questions, still trying to learn! LOL

Thanks again.

Marnet
…still reading, still learning

The People Who Frequent This Site Are Car Lovers, Too.
Sometimes It’s Difficult To Help Those Who Don’t Really Try And Take Care Of Their Cars (Often To The Point Of Abuse) Or Don’t Appreciate The Help They’re Getting, . . .

. . . But It’s Enjoyable And Rewarding To Help People Who, Like Yourself, want to care for your car, want to learn, and appreciate the help. That’s what keeps us coming back.

Don’t forget, we’re learning from you, also. I’ll defer the whine question to the others and I’ll wait to learn along with you.

CSA (We love the 2 Impalas in our family.)

I want to echo the OP’s sentiments. I know enough to be dangerous, if even that much - but I enjoy the process of identifying symptoms and then seeing how my (barely) educated guesses match up to my mechanic’s assessment. I read this post today b/c I took my Jeep in for a similar whine - increases with RPM, no change when steering, some searching for fourth gear and what feels like an engine hiccup - all following an engine swap 2,000 miles ago. Hoping for a simple belt tensioner or something, but still learning as I read more here.

Reading it fine but why revive it after 8 years of inactivity ?