C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

69 Noise on deceleration

Thread Tools
 
Search this Thread
 
Old Nov 15, 2015 | 02:55 PM
  #1  
dshawster's Avatar
dshawster
Thread Starter
Instructor
Liked
 
Joined: May 2015
Posts: 133
Likes: 12
From: Maple Valley WA
Default 69 Noise on deceleration

I have a noise coming from the car that I'm pretty sure is the differential and it only happens when I decelerate, no noise when steady speed or under acceleration. I suspect the diff because I pulled it a few weeks ago to change the seals while I was swapping the rear spring, I set the pre-load at about 5 in-lbs but I'm wondering if I didn't get the pre-load just right if it would cause an issue like this. I want to confirm before pulling it again but I'm 95% sure it is the diff because its the last thing I touched! I appreciate any help in advance.
Also I just re-installed trailing arms rebuilt by Bairs because of a bad wheel bearing on the passenger side, this is originally what I thought the cause of the noise was.

Dave
Reply
Old Nov 15, 2015 | 03:20 PM
  #2  
toobroketoretire's Avatar
toobroketoretire
Melting Slicks
 
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Default

Originally Posted by dshawster
I have a noise coming from the car that I'm pretty sure is the differential and it only happens when I decelerate, no noise when steady speed or under acceleration. I suspect the diff because I pulled it a few weeks ago to change the seals while I was swapping the rear spring, I set the pre-load at about 5 in-lbs but I'm wondering if I didn't get the pre-load just right if it would cause an issue like this. I want to confirm before pulling it again but I'm 95% sure it is the diff because its the last thing I touched! I appreciate any help in advance.
Also I just re-installed trailing arms rebuilt by Bairs because of a bad wheel bearing on the passenger side, this is originally what I thought the cause of the noise was.

Dave

Are you saying you replaced the 3rd member's side yoke seals and the pinion seal? A turning torque of 5 in/lbs is a lot lower than usual but it wouldn't cause a noise that I can think of. If a rear tire isn't inflated enough it'll cause more noise than usual so check the pressures. I recently found tires don't bulge hardly at all until the pressures drop to 5 psi or less so you can't tell by looking at them.
Reply
Old Nov 15, 2015 | 03:58 PM
  #3  
dshawster's Avatar
dshawster
Thread Starter
Instructor
Liked
 
Joined: May 2015
Posts: 133
Likes: 12
From: Maple Valley WA
Default

Originally Posted by toobroketoretire
Are you saying you replaced the 3rd member's side yoke seals and the pinion seal? A turning torque of 5 in/lbs is a lot lower than usual but it wouldn't cause a noise that I can think of. If a rear tire isn't inflated enough it'll cause more noise than usual so check the pressures. I recently found tires don't bulge hardly at all until the pressures drop to 5 psi or less so you can't tell by looking at them.
I did replace the pinion and yoke seals, put friction additive back in and oil. The sound almost sounds like tire rub but I don't see anyplace where it would be rubbing. I will check the pressures to eliminate anything caused by that.
Reply
Old Nov 15, 2015 | 04:10 PM
  #4  
toobroketoretire's Avatar
toobroketoretire
Melting Slicks
 
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Default

Originally Posted by dshawster
I did replace the pinion and yoke seals, put friction additive back in and oil. The sound almost sounds like tire rub but I don't see anyplace where it would be rubbing. I will check the pressures to eliminate anything caused by that.

Sometimes the parking brake cables will rub the inside of the tires so check those too. They would be shiny if they were rubbing. The cause would be a missing retainer clip where the cable housing attaches to the trailing arm. Also if the transmission mount is broken the tail housing can shift back and forth sideways upon acceleration and deceleration so you could check that too. Are you running stock size tires?

About a month ago I started a thread "Tire Bulging At Low Pressures" after performing some tests in my garage. I found a tire hardly bulges at all until the pressure drops below 5 psi. So its impossible to judge the tire pressure by just looking at it. The more a tire bulges the more it rides on it's outer edges and that makes noise that resembles driving on a rough surface road.

Last edited by toobroketoretire; Nov 15, 2015 at 04:30 PM.
Reply
Old Nov 15, 2015 | 04:48 PM
  #5  
dshawster's Avatar
dshawster
Thread Starter
Instructor
Liked
 
Joined: May 2015
Posts: 133
Likes: 12
From: Maple Valley WA
Default

[QUOTE=toobroketoretire;1590910468]Sometimes the parking brake cables will rub the inside of the tires so check those too. They would be shiny if they were rubbing. The cause would be a missing retainer clip where the cable housing attaches to the trailing arm. Also if the transmission mount is broken the tail housing can shift back and forth sideways upon acceleration and deceleration so you could check that too. Are you running stock size tires?

Running brand new stock tires on stock rims. I'll check the mounts to eliminate that, its not the parking brake cables I just re-installed those yesterday and made sure they were in their mounts and had clips installed. I'm also leaning towards it being a u-joint, I had a similar situation in my truck years ago under deceleration, but the noise was a lot different.
Reply
Old Nov 15, 2015 | 08:16 PM
  #6  
LT-1 kid's Avatar
LT-1 kid
Melting Slicks
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2007
Posts: 2,149
Likes: 284
From: cary Il
Default

I had the same type of noise from my 69 BB, it had a bad ujoint not fully seated
at the outer half shaft. also check the drive shaft ujoints
Reply
Old Nov 16, 2015 | 12:04 AM
  #7  
dshawster's Avatar
dshawster
Thread Starter
Instructor
Liked
 
Joined: May 2015
Posts: 133
Likes: 12
From: Maple Valley WA
Default

Originally Posted by LT-1 kid
I had the same type of noise from my 69 BB, it had a bad ujoint not fully seated
at the outer half shaft. also check the drive shaft ujoints
I'm going to jack it up tomorrow and take a look at them, I hope it isn't the diff.
Reply

Get notified of new replies

To 69 Noise on deceleration





All times are GMT -4. The time now is 06:08 AM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-9
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE