C2 Powerglide Noisy at Idle

[Bruce Boatner]

I am a first time Corvette owner who just purchased a 1964 with a Powerglide. While in park or neutral, the transmission makes a very noticeable "whirring" noise. My first hope is that the noise is just a characteristic of the Powerglide, but the volume of the noise and common sense tells me that something may be amiss. When I shift into gear, the noise goes away completely and the transmission seems to operate flawlessly in every other respect. I would appreciate any insights anyone has on this. I drive the car just about every day and hope I am not slowly destroying the tranny in any way.

I am still overwhelmed at how knowledgeable and helpful everyone on this site has been. Hopefully, I will be able to return the favor one day.

[William C.]

Re: C2 Powerglide Noisy at Idle

I believe the noise you describe is "Typical" of a PG in park or neutral. I don't know why, maybe an auto trans person can help, but I've been noticing it in PGs now for about 40 years.

[Bruce Boatner]

Re: C2 Powerglide Noisy at Idle

Bill,

Thanks--that was the answer I was hoping for. This is my first experience with a Powerglide (mine or anyone else's) and I have never heard a noise like this with any other transmission. I would be curious to know the "why", but can live without the answer as long as I don't have worry about picking up pieces of my transmission from the highway anytime soon.

[Joe L.]

Re: C2 Powerglide Noisy at Idle

Bruce-----

I know virtually nothing about Powerglide transmissions; I don't think that I've even driven a car that had one in over 30 years. However, one thing that often happens with these old cars is that we tend to judge their performance and characteristics by the "standards" that we're familiar with. In other words, by the standards of modern-day cars. That's completely natural and normal, too. Whether it be the transmission, the radio, or whatever. Even, the fumes we notice in the garage after we've parked one of these old cars for the night might seem "abnormal" to us.

Things have changed a lot, though, in the 40 years, or so, since these cars were built. We often complain about how much better things were in the "old days" and, certainly, some things have changed for the worse. But, a lot of things automotive have changed for the better. The hoardes of engineers, scientists, and technicians devoting multi-million man hours over the past 40 years to automotive research and development have not been without accomplishment.

As far as transmissions go, there have been quantum leaps in performance. The electronically controlled, TurboHydramatic transmissions of today's GM cars are magnificent in all respects as compared to the Powerglides of days of yore. Even the THM-400 which goes back to the mid-60s and is now known as the 4L80-E has changed rather dramatically over the years. The 4L60-E used in current Corvettes is built at the same Toldeo, OH factory as the Powerglides installed in Corvettes in the 60s, but that's about all they share.

Don't misunderstand, though. It's definitely a good idea to check out any suspected problem as you are doing; you never know when something is "how it's supposed to be" or "a major problem about to happen".

[Kevin M.]

Re: C2 Powerglide Noisy at Idle

Humm, I have a powerglide and there is no noticeable change in the sound it makes at idle. The only difference I notice, in park or neutral, is a rise in engine RPM. I assume it's because the transmission is not engaged, the tach rises also. I hope another powerglide owner chimes in because I've been known to be wrong, or deaf in this case, or maybe the radio is too loud.

Kevin

[Roy B.]

Re: C2 Powerglide Noisy at Idle

The cast iron tranny can be noisy in PARK if there is pressure on it like on a hill holding the car back.It's the planetary gears turning inside. But the aluminum tranny should not, being improved over the cast iron. Eather tranny having a high noise factor is a sign that the Trust washers or needle bearing in the planetary gears are wearing. Remenber the planetary gears are turning while in Park or Neutral ( when the Corvette is not moving). And stop moving when you put it in gear ( but you don't notice the noise as your drive away.)

This noise can go on for a vary long time ( years) before it needs attension, but I would think down the road to have it fixed.

[andy #28359]

Re: C2 Powerglide Noisy at Idle

Bruce,

I have 2 aluminum Powerglide cars, one of them a '68 Chevelle my dad bought new in '68, the other my '65 Corvette. Both cars have always made the sound you mentioned in PARK and NUETRAL. Whether just rebuilt or about to blow-up they make the same noise. A friend of mine has a '66 Chevelle with a 'glide, same exact sound. Very easy to tell if a car has an aluminum 'glide in it just by listening while it's NOT in gear.

[Roy B.]

Re: C2 Powerglide Noisy at Idle

Bruce I should have said not as noisey as the cast iron but they may make noise.It's rare a shop will change the planitary gears for a little noise problem in the roller bearing area.

[Kevin M.]

Re: C2 Powerglide Noisy at Idle

Having re-read the post above and thinking about how my car "sounds", there is a difference in the sound a powerglide makes in neutral/park and when it's in gear. This was never a loud noise to me just the operational function of the transmission. I can now associate the different sounds to the description of the planetary gears as they engage and un-engaged.
Thanks for toady's lesson.

Kevin

[Wayne W.]

Re: C2 Powerglide Noisy at Idle

Heck, I thought all of them did it. Just a part of the PowerSlides demeanor.

[frank mccracken]

Re: C2 Powerglide Noisy at Idle

I agree Wayne. 'Glides make that whirring noise, always have, always will.......

[Mark F.]

Re: C2 Powerglide Noisy at Idle

Bruce:

The Powerglide in my '65 convertible makes the exact same noises in Neutral and Park. Everthing seems OK, though, and has been for the 2000 miles since I bought the car.

Mark

[Bruce Boatner]

Re: C2 Powerglide Noisy at Idle

Mark,

Thanks for your input--makes me feel much better. I can certainly live with the noise as long as it is normal and not a sign of bad things to come. I may just be a little paranoid, but you have to admit, the noise can be a little disturbing if you are not expecting it.

Bruce

[David Z.]

Re: C2 Powerglide Noisy at Idle

OK! Nice to know that "whirring" noise that my PG coupe makes in park and neutral is "normal". I've had mine a little over two years now. Former owner paperwork indicates a rebuild about 5 years ago with low mileage since then. It's always made the noise you folks are describing. Maybe a little louder during cooler weather startups. Ah normalcy! Maybe on the plus side, everybody tells me PG's are "bulletproof".

Thanks for the CEU's
DZ