Drive-line noises

[old cool]

Hello. My name is Ted. I am a new to this forum/site. Recently purchased a great looking, 90% restored 1966 GMC swb. User name: "old cool"

I have enjoyed reading various threads. There are tons of good questions and/or words of experience that we can all benefit from.

Question: What are the possibilities for drive-line noises that permeate the inside of the cab? I'm not referring to road noises that come from a truck that originally came with little to no insulation (or am I?). The most significant noise (whirring or whining) comes between shifting and and then while driving is 3rd.
Notes:
1. I've repacked wheel bearings and correctly adjusted same.
2. The seller said he replaced rear axle seal and found no evidence of ring and pinion deformities or shavings. He did suggest that "pinion seal behind yoke may be too tight" (his words). He also changed rear end fluids and repacked bearings. He also indicated that the whining noise was same before and after he performed the work.
3. Seller said it had Timken bearing upgrade.
4. I attempted to lube the u-joints. Couldn't get front fitting to accept lube and rear fitting in not accessible unless you remove u-joint.
5. The sound is more central to cab. It doesn't sound front or rear. But I realize that could be deceiving since sound has a mind-of-its-own on an non-insulated vehicle. Looking forward to feedback. Have a great day!

[old cool]

Merged two identical threads into this single thread. Removed this post as it was a double of the above post.

Thanks all.

[Keith Seymore]

Need more detail:

Is it a "white noise" (aka "hashy" "trashy", like a wind noise)?

Is it a high frequency pure tone?

Is it vehicle speed dependent?

Is it engine rpm dependent?

Is it a stick shift? Does it happen (mostly) just when you push the clutch in?

Perhaps since you are local to me we could get together and go for a ride (...if the weather ever clears up...).

K

[old cool]

Hi Keith, I have a little more info now. It's a new vehicle to me and I haven't driven much. So.....
It is high frequency and happens when I push clutch in and drive along in 3rd. Everything sounds old school normal when I'm accelerating. Sound becomes very apparent when coasting, clutch in, and as I said, easy, steady driving in 3rd. Hate to put it this way but I didn't know what you meant by hashy, trashy so I thought you were kiddn around. My descrip would be vrrrrrrrrrrrr, front/central to cab, and not noticeable during acceleration. Saw your feedback to a post about vibration which led me to get back with you. I have suspected drive shaft/u-joints. Thks . Ted

[old cool]

Anyone know why I can't find earlier responses? 66submarine sent videos, and others sent feedback on ujoints. All were helpful. Maybe I'm not using forum links correctly. Help.

[Keith Seymore]

You had a couple threads started and the other one got quite a few more responses. I suspect those are over on the other thread:

http://67-72chevytrucks.com/vboard/s...29#post6657829

K

[Keith Seymore]

Are you familiar with what rear axle "whine" sounds like (gear mesh frequency)?

The fact that it is (a) throttle/load dependent (b) that you "hear" it rather than "feel" it, and (c) that the previous was in there goofing around is beginning to make me wonder if it is gear mesh whine.

K

[old cool]

Hi Keith,
If gear mesh frequency (gmf) sounds like the video sent to me by 66submarine then yes, I have that sound. otherwise, im not sure what gmf is.
I hope im not repeating myself, but my latest input is most accurate: I don't get the whine until I push clutch in (free wheeling) and while cruising in third. Taking off I hear the rev of the engine with that old, noninsulated truck sound. That is, it sounds normal in first and second during acceleration. Thanks again for input.

[old cool]

I think I got started with this thread. lol. Anyway, I moved on to timing problems, alternator alignment issues, popping noises, drilling muffler hole, etc. Still dealing with some issues; others fixed. So, I'm back on the drive-line issue because I found a thread that was more definitive than mine. (Humming while coasting; hence, clutch in and in 3rd gear with little load. Hope this helps others seeking a description. See thread 386889.
My sincere thanks to all that tried to help me.
I've been posting a little less as I have been taking advantage of the Q&A section.
God Bless. Hope everyone had an enjoyable 4th.

[siggyfreud]

Had something similar in mine years back. I replaced the u-joints and re-balanced the driveline at the same time. One of them fixed it, but couldn't tell you which. Hearing the sound in the cab tells me it could be driveline related, as the sound could travel up the shaft and then echo into the cab via the transmission mounting being direction underneath.

[old cool]

Thanks for responding. You mentioned that you re-balanced the drive line. Are you referring to drive shaft? Also, does anything need to be checked or tightened on the transmission mounting (3 speed). Lastly, the yoke is exposed about one inch before it enters trans. Is this normal?

[siggyfreud]

Yes, I meant balance the driveshaft. They actually ended up just replacing the shaft and reusing the ends.

Yes I'd also check the transmission mount and ensure it's snug and not off-kilter.

Has the truck always had this or is it a new development?

[siggyfreud]

I think having the yoke exposed an inch is normal. Mine wasn't seated all the way in the trans.

[66Submarine]

"The most significant noise (whirring or whining) comes between shifting and and then while driving is 3rd."

Do you mean it whines when you push the clutch in, and also whines in high gear? Whirring with the clutch pushed in will probably be the throwout bearing; whining in high gear probably means the ring and pinion have a lot of wear or are set up incorrectly. I'd be weary of the pinion bearing preload on a rear end with a crush sleeve like that if someone's been messing with it that didn't know what they were doing, but too much shouldn't make it loud, although too loose certainly would if he put a new crush sleeve in and didn't crush it down until the preload was what it should be.

Any chance of a video clip going down the road to see what it sounds like?

[66Submarine]

BTW, if it's the ring and pinion, you'll notice it will get much quieter/louder based on whether or not it's under load. (IE, pulling a hill vs. coasting in neutral)

[jtrichard]

could have been ran way low or out of oil also and smeared the gears you'll never get rid of the noise if that's what has happened... also if the setup was wrong and ran for some time like that you cant get rid of the noise

[old cool]

Appreciate the feedback.
To siggy. I just bought the truck. However, the person I bought from said both he and previous owner were knowledgeable of sound. He also said he believed it to be ring and pinion even though sound comes through center of truck. Perhaps in time I will report more info. We've had rain all week so driving has been limited to a few miles.

To submarine: I had a bad throwout bearing in a 71 car. Though it's been over 20 years ago, it doesn't remind me of a clutch component. Also told all was new in restoration. The sound comes throughout shifting and driving. Sound comes during normal driving with little load but clutch is out. When I drove it home (last Sat) I drove on freeway at 60-65. Nothing seriously loud or annoying. On next drive around town, noise was more profound and at low speeds. I'll get back on whether it gets louder or quieter, and at what point in acceleration, deceleration, or in 3rd gear operation. You need more info and I need to provide better description. Ill get it out this weekend.

To jtrichard: The man I purchased from was former GM service manager and had a ton of experience. As mentioned in my initial post, a rear axle seal was put on and an inspection performed. All gears and oil checked out fine. Nothing deformed and no metallic in r-end oil. However, this is trusting a seller. He pointed out that the noise was same before and after his work. That's what led me to ask about other causes such as drive shaft and/or u-joints. I'll get back with more precise details.

Thanks gentlemen. What I'm now certain of is that this is not a normal sound and it could be caused by several different things.

[old cool]

To sharps40: You may be on to something. It is a sound that radiates around trans. Any fix in a bottle (like zinc stuff) to quiet it? Whoever rebuilt it prob went with old gears as the truck shows many original parts and tags. Funny, the shift boot is exposed from underside. That'll let the noise in. More detail to come. THNKS!

[66Submarine]

In 3rd/high gear the transmission's gears are not under load (the input and output shaft are locked together), so you shouldn't really hear any gear noise from it, even if the gears and associated rollers are shot. Only the input and output shaft bearings are really doing anything. In all the other (reduction) gears it'll very probably whine to some extent, even when nothing is really worn out.

The whine getting suddenly louder isn't right, but it's far from uncommon to hear a worn ring and pinon howl a little going down the road. Being 48 years old, it may very well have many hundreds of thousands of miles on it, and someone could have also run it low of oil and messed it up some. One of my trucks spun a carrier bearing and chewed the gears up in the past--that one REALLY howls going down the road!

Here's a clip showing the ring and pinion noise:

Rearend whine - YouTube

[old cool]

To all of you, a hearty thanks.
Thanks for both you tube videos 66submarine. The first one you sent from under the truck does sound like my truck. I noticed the sound was most apparent in first couple of gears but quieted down in high gear - until you let off gas and then stepped on it again. If the rain would ever stop I'd be able to get back with better descrip. By the way, is the whining sound in that video normal or is that a ring and pinion problem? Also, would that sound carry up quite loudly through cab as mine does?

[66Submarine]

And for some shameless self-promotion, here's a clip of my own truck showing the totally normal and inherent gear whine from the old heavy duty truck four speed.

1965 Chevy C30 250/SM420 drive up the street -...

[siggyfreud]

When I had my issues it was definitely more of a whirring noise than a whining noise. Was a "Voom, voom, voom, voom" type of thing.

[66Submarine]

I forgot to mention, but the thing to note is that the loud truck trans becomes pretty much silent when I pull high gear/1:1.

[66Submarine]

Glad I could be helpful!

The first clip would be ring and pinion noise like you get from extreme wear or other problems, and it is heard just fine in the cab IME. So that's probably what you're hearing/experiencing. A truck with a lot of miles and wear will normally make a little noise IME, but if it's real loud then you might have issues, and I would be especially concerned if it has became louder quickly, because that would mean something is failing.

The truck I have that's real loud is like that mainly because it was damaged when a bearing failed, and it has been like that for tens of thousands of miles now. Likewise, my current truck has a lot of miles on it and you can hear the ring and pinion, but that's because of hundreds of thousands of miles of wear. For gears to suddenly become much louder indicates something failed/is failing.

In first and second gear, you are probably just hearing the sound of the transmission whining in addition to the ring and pinion, making it seem louder.

[old cool]

66 Submarine. Apparently I entered my very first post twice. Hence, Im getting responses on two threads for the same question. Newbie mistake.
I have learned more about my truck's sounds. First gear during acceleration is pretty much all rev with some very slight whine mixture. Then when clutched is depressed, whine becomes quite loud "vrrrrr". Then shift to second and accelerate and mostly engine rev again. Depress clutch and I hear whine again. While driving in 3rd and maintaining a speed, I hear whine steadily. Letting off-and-on gas changes the pitch momentarily. Like your first video from beneath the truck. FYI, I put the truck in neutral while coasting down hill and it became quieter. Hope this analysis tells the story accurately. Goin driving now. Suns out! Thanks again!!!