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

rear knock

Thread Tools
 
Search this Thread
 
Old May 20, 2024 | 01:16 PM
  #1  
scott1959's Avatar
scott1959
Thread Starter
Instructor
Conversation Starter
All Eyes On Me
 
Joined: Jun 2019
Posts: 126
Likes: 3
From: Hatfield, Pa.
Default rear knock

Have a 69' 427 with automatic transmission. Just took car out for first time in last 6 months. Noticed a knock in the rear area of car just about every time I let off the gas . Have any ideas as to the cause of this?
Thanks.
Reply
Old May 20, 2024 | 01:25 PM
  #2  
Bikespace's Avatar
Bikespace
Race Director
Liked
Loved
Community Favorite
Top Answer: 1
 
Joined: Mar 2017
Posts: 11,949
Likes: 4,507
From: Virginia
Default

Mechanical? Differential snubber bushing?

In the exhaust? Afterfire from lean misfire?
Reply
Old May 20, 2024 | 02:04 PM
  #3  
Tampa Jerry's Avatar
Tampa Jerry
Le Mans Master
20 Year Member
Active Streak: 30 Days
Active Streak: 60 Days
Top Answer: 1
 
Joined: Aug 2005
Posts: 6,541
Likes: 1,975
From: Temple Terrace Florida
Default

If you think it's suspension related, check to see if the shims in frame pocket where the trailing arm connects to the frame. While there, check to see if the bushings are intact. Jerry
Reply
Old May 20, 2024 | 06:30 PM
  #4  
SEVNT6's Avatar
SEVNT6
Le Mans Master
15 Year Member
Active Streak: 120 Days
Liked
Top Answer: 5
 
Joined: Jan 2007
Posts: 7,999
Likes: 3,338
From: Omaha NE
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2022 C3 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
Default

Originally Posted by Bikespace
Differential snubber bushing?
That's what it was for me...
Reply
Old May 20, 2024 | 07:05 PM
  #5  
4-vettes's Avatar
4-vettes
Race Director
15 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Nov 2006
Posts: 13,229
Likes: 7,825
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Default

U joints, snubber bushing, trailing arm bushing? We can all guess all day but maybe you should get under it and check it out!
Reply
Old May 21, 2024 | 07:32 PM
  #6  
Rescue Rogers's Avatar
Rescue Rogers
Is my vette stock?? HAHA
Supporting Lifetime Gold
Veteran: Navy
10 Year Member
Community Builder
Loved
 
Joined: Oct 2015
Posts: 20,212
Likes: 9,350
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Default

check out the snubber and all of the associated bolts like has been suggested. THats exactly what they do
Reply

Get notified of new replies

To rear knock





All times are GMT -4. The time now is 02:16 PM.

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