Hey guys.........I'm new to the board. Had a friend turn me on to this site. He gave you all a thumbs up. Here's my problem......I have a 69 camaro with a 350 ci ,.030 over- with a turbo 400 B&M tranny, a 12 bolt from a 68 chevelle (at least part of my car is a chevelle)The problem is that I have a noise when going down the highway ........say at 70 mph and when the car levels off at this speed and the tranny is in the "no load" point ....it almost sounds like a wheel bearing going out. I have just had the entire rear end redone. New rebuilt carrier (went from a 4 series that was messed up to a 3 series) New seals and bearing thru out the rear end. New 3:73 gears. The only time it makes this noise is at he no load point. Accelerating and de-accelerating it is quiet. I use the "wheel bearing noise" as a tool to let you know what it sounds like. I have changed the drive shaft---no worky. The tranny has been rebuilt. This is driving me nuts. Points of interests:

1. If it was a wheel bearing........it should do it all the time

2. I put stethascope to the diff housing while on jack stands......all quiet.

3. Had new u-joints put in......no worky, traded drive shafts with a buddy....no worky

4. Possibilities......still something in the rear end, pinion angle, out put shaft on the tranny.

Definately drive line related. Motor is smooth up to 6k (neutral) Sorry for the long post.....any input would be appreciated. thanks in advance for your help.

So..... if you kick it into Neutral at 60 or 70, the noise is still there? And you have all stock RUBBER bushings on the rear end?

I guess I could be wrong but, I didn't know a 3.73 gear would work on a series 4 carrier. I thought that was for 4:11 and up.

Yes the noise is still there in neutral and every bushing on the car is brand new polyurethanes.


2nd reply.........your right, I had a 3 series carrier put in to replace the 4 series. That way it matches the casting number on the axle housing. Not to mention the series 4 carrier was messed up.

Sounds like you have covered most of the bases I can think of. Have you considered the torque converter? Maby Jakeshoe could comment. Sorry I can't help, but I can push you to the top.

Billy graemlins/waving.gif

Thanks for the push. For the highway noise.........no can not be the torque convertor. I can shift into neutral and the noise is still there. I have the car on all 4 jack stands. I will crank it up tonight and get it up to 60 mph and go from front to back with a stethascope. I'm gonna find where the hell this noise is coming from. I absolutely hate dumps for getting under a car while running :mad:

Do you need me to come over and help? I can just picture Cindy in the car revving the engine to redline as you and your creeper shoot out the back and down the street :eek: . LOL,LOL.

Seriously, you need someone there to help you. You don't want to wire your throttle open and crawl under that car by yourself!

Billy :D

Originally posted by Billy:
Do you need me to come over and help? I can just picture Cindy in the car revving the engine to redline as you and your creeper shoot out the back and down the street :eek: . LOL,LOL.

Seriously, you need someone there to help you. You don't want to wire your throttle open and crawl under that car by yourself!

Billy :D Hell..........I could always use and extra ear. BTW......I just screw the idle screw in. And yes it makes me nervous. You have to admit I would look like some new hotwheel car shooting across the street on a creeper. :D

Loose pinion nut on the rearend maybe?

Had a similiar situation on my car a few years back....only made a light grinding noise under no load condition.....pinion nut was loose allowing pinion gear to rub back against the ring gear.


Just a thought.

Originally posted by Daytona Jeff:
Loose pinion nut on the rearend maybe?

Had a similiar situation on my car a few years back....only made a light grinding noise under no load condition.....pinion nut was loose allowing pinion gear to rub back against the ring gear.


Just a thought. Good thought.....but no such luck. New gears...new nut with in the last 2 weeks. Pulled drive shaft and grabbed the yoke......very tight.

Well........even had Billy come over. Still can not isolate the noise. graemlins/angry.gif

You sure the gears are set up properly?

Check driveline angles, pinion angle off will cause some goofy noises. If all was stock I'd condem the gera set right away, we've had problems with bad set-ups causing a noise within the gears. Side note, once a wear pattern has develped in a gears et it is almost impossible to get it to go away even if the diff is reset. Lots of adjustments, easy to make a mistake when building, I wouldn't fault the builder. i build a half-dozen a month and a few a year come back to bite me.

I would guess the rear setup too.
Just because it was just done doesn't mean it is right.
Have you checked the fluid in the rear?
Pull the cover and take a pic of the pattern and post it...

Make sure it is full of fluid (new rear will eat a bit filling everything up and coating it).
Check for metal in lube.
Look at pattern.

Usually a ring and pinion make a "howling noise", not so much a "pulsating whirring" noise like a bearing.
You could have a bearing out in the rear or the ring and pinion, but the noise will be different between the two.

How did the axles look?

While you have the cover off, check the backlash, even if just by hand, see if it nice and snug, or sloppy.

Originally posted by Dean:
You sure the gears are set up properly? I can only go by what the guy told me. They are set up a 7 thousandths. I had the carrier replaced, the new gears, all new bearings thru out. The noise has not changed.

[QUOTE]Originally posted by jakeshoe:
[qb] I would guess the rear setup too.
Just because it was just done doesn't mean it is right.
Have you checked the fluid in the rear?
Pull the cover and take a pic of the pattern and post it...

Make sure it is full of fluid (new rear will eat a bit filling everything up and coating it).
Check for metal in lube.
Look at pattern.

Reply


I had Edwards automotive to it in Arlington, Tx. I had a couple of guys that were at the place I buy my camaro parts from recommend him. Supposably he knows 12 bolt rear ends better than any one. Every bearing and shim in the rear end is new.He said he set it up a 7 thousandths on the backlash. I was not there. He said he looked over the axles and they were fine. He even stated if they looked bad, he had an extra set that he could make me a deal on. But it was not needed. Here are some basic facts about my problem:

1.)Only makes the noise in a no load situation on the highway or on jackstands
@
2) With a stethascope ...differ. housing is quiet. Axle housing is quiet. Small amount of noise from tailhousing of tranny. Nothing bad. Hubs for wheels are quiet.

3)Noise occurred when 12 bolt was put in. What had changed in doing so....pinion angle--somewhere in the 5 degree zone, only thing left in the 12 bolt that is orginal is basically housing and axles.

4)Noise if I could truly isolated where it is coming from...thats a big if...Passenger rear maybe.

5)under a load, no gear noise what so ever whether it be accelerating or de-accelerating.

6) Known fact...drive shaft has a little wobble to it. Used a friends drive shaft and did not change noise.

Contradictions:

Bearing.........bearing would make the noise all the time.

Gears....Possibility...but I have had two sets of gears put in. Second set with different carrier...chances of the noise being the exact same.....possible, but not likely.

Axle housing misalignment...would make noise all the time. I would think.

Pinion angle ........the only thing besides not knowing 100 percent that the gears are set up right is the only thing I have not tried to change. I did try to put a jack as close to the nose of the differ. to push up to loose a degree or two. No noticable change.

I will try to pull the rear cover and do a patern on the gears this weekend.

Best possible analogy of the noise.......would be the sound a bad wheel bearing would make. Not exactly but the closest I can come up with .

A close second......Muffler rubbing against the drive shaft ......pretty bad.

Originally posted by SSMAN69:
Best possible analogy of the noise.......would be the sound a bad wheel bearing would make. Not exactly but the closest I can come up with .

A close second......Muffler rubbing against the drive shaft ......pretty bad. Oh...no howling ....I have had gears to tight and to loose. No relation in sound.

Originally posted by SSMAN69:
Best possible analogy of the noise.......would be the sound a bad wheel bearing would make. Not exactly but the closest I can come up with .

A close second......Muffler rubbing against the drive shaft ......pretty bad. Basic fact.......the faster the car goes the more apparent the noise gets.....once again..only in the no load zone. Other than that ...all is quiet.

Billy.....if I have left out anything...feel free to chime in. ;)

Perhaps this page may be of help? I found it very informative.

http://www.vibratesoftware.com/html_help/html/Diagnosis/Reference/Drive_Axle_Problems.htm

Rob

OK,
SO we'll assume it is not the rear or driveline since these items have been changed.

Will it do it in 2nd gear.
Put the trans in manual 2nd and run it up to speed and see if the noise is there.

Scored up intermediate sprag overruns in 3rd when you coast, it could be noisy.
In 2nd it would be locked and not overrunning.

Originally posted by jakeshoe:
OK,
SO we'll assume it is not the rear or driveline since these items have been changed.

Will it do it in 2nd gear.
Put the trans in manual 2nd and run it up to speed and see if the noise is there.

Scored up intermediate sprag overruns in 3rd when you coast, it could be noisy.
In 2nd it would be locked and not overrunning. As long as its not raining......I will try 2nd after work today. I want to say it did it in nuetral while going 70.........but I will have to try that again to make sure. My mind is starting to overload with all the tests. I haven't tried the 2nd gear thing yet.

I had the tranny rebuilt earlier this year.I broke the intermediate hub.......I think thats what they called it....it was a housing with a snap ring on the snout. I broke the end of the snout completely off. Springs were just laying loose in the tranny. No sprags were replaced that I know of.

When I let Billy drive it yesterday.......I could barely hear the noise at about 30 mph. The car is a little loud with 3" exhaust and superturbos and dumps. I am usually pretty good about running down rattles and noises. THis is a lu lu. Its just damn hard to be under the car with dumps and take your time looking over everything. Chokes you out.

Originally posted by rusty66:
Perhaps this page may be of help? I found it very informative.

http://www.vibratesoftware.com/html_help/html/Diagnosis/Reference/Drive_Axle_Problems.htm

Rob THanks.......I will print it out and set it by the toilette.......I do my best thinking there. ;)

You're very welcome.

Do yourself a favor and buy a six pack of castor oil ....., but be sure not to switch papers. You might get confused reading the wrong article.

Originally posted by rusty66:
You're very welcome.

Do yourself a favor and buy a six pack of castor oil ....., but be sure not to switch papers. You might get confused reading the wrong article. LOL! I hear you.......its sad but.....when your married with kids........thats the only quiet time I get. :D

Did you check driveline angle?.....

SS, I thought about it most of day(while building a Dana 44)I am pretty sure your guy's set-up is off. .007" is not that great, a little loose for me but that has nothing to do with the set-up. Backlash is easily adjusted and usually doesn't cause any noises at speeds. Pinion depth and gear pattern are much harder to set and USUALLY cannot be undone once the ring/pinion have devoloped a pattern. I have fixed diffs that already set, but usually you just move the noise to a different frequency. Good Luck

Barry, I can't really think of anything profound to add. You have pretty well described the same thing that I heard. I have kind of set back on this one so as not to dilute or confuse the folks that are trying to help.

The one distinctive thing about this noise is that it truly sounds like a metal on metal grinding. It is not just a transient noise.

The peculiar thing that I noticed is that when you are in the car (facing forward) it sounds like the noise is coming from the tranny. You would swear it is right below your feet. Then when you turn around to listen in the back you would swear that it is coming from the rear end.

After thinking about it overnight, it truly seems to only happen when there is a no load condition only. I interprit this to thrust because this is what you and I work with daily in the industry that we are in. When you are accelerating this applies a positive thrust to one end of the driveline. When you are decelerating you are in somewhat of a negative thrust on that same end (actually the applied thrust switches ends). The noise only occurs when you have no thrust applied to either end. The point I am trying to make is that in this situation ( I would think) all your componants go to a relaxed state. Maybe this is why the backlash and other tolerances are so important. I still have not figured out why the grinding noise is only evident when the componants are in a relaxed state.

It might also be interesting to know if the same thing happens in reverse. I don't really know why, but it would be interesting to know.

Now that I have completly confused the issue, I will go back to bed. Sorry for all the theoretical BS, but you know how I am when I get trapped up inside my head and can't get out! :D


Billy smile.gif

Originally posted by Metalmechanic:
Did you check driveline angle?..... .


That is a great possibility. It is definately drive line related. From tranny back.

I still have to do one more thing to rule a great possibility out. Set the pinion angle. It almost makes since to me that if the angle is beyond the max......at no load speeds....the u-joints would cause the drive shaft to vibrate and make the noise its making.