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

Clunk when downshifting

Old Aug 31, 2016 | 01:31 PM
  #1  
Bhebert449's Avatar
Bhebert449
Thread Starter
Pro
 
Joined: May 2013
Posts: 570
Likes: 22
Default Clunk when downshifting

I have a 69 bb 4 speed coupe and when downshifting to slow the car I sometimes get a clunk coming from the underside of the car. Also, when in third gear and decelerating, the car sometimes pops out of gear.

My question is are these issues related? The car is currently in the shop to have these along with a few other minor issues inspected. I was told the drive shaft was out of alignment so they are sending it off to be repaired. The u-joints checked out ok. Do I have a transmission problem? I was also told when they removed the yoke from the transmission after pulling the drive shaft that it had some wear to the end that connects to the transmission. They said it was chewed up.

Should I have the transmission pulled and rebuilt?
Reply
Old Aug 31, 2016 | 02:02 PM
  #2  
domenic tallarita's Avatar
domenic tallarita
Burning Brakes
10 Year Member
All Eyes On Me
Top Answer: 1
Top Answer: 3
 
Joined: Aug 2013
Posts: 1,071
Likes: 322
From: palm springs ca
Default

When you let off and it pops out of gear it (in most cases) are the syncros. The gear has part of the syncro on it and there is a syncro clutch which is the shift slider. That could be out of adjustment (linkage) but when a gear grinds it is the syncro part of it grinding against the clutch ring in the trans.
The clunk can be your differential rubber snubber. If the yoke is bad along with popping out of gear, a good trans guy can cut thru the chase by checking the linkage, then taking the side cover off the trans.
A few bad shifts under power can dull the dog house parts of the syncro that is on the gear and clutch ring. the brass part of the syncro only slows the gear down to engage it.

Dom
Reply
Old Aug 31, 2016 | 04:21 PM
  #3  
Easy Mike's Avatar
Easy Mike
Team Owner
Supporting Lifetime
20 Year Member
 
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Default

Originally Posted by Bhebert449
...The car is currently in the shop...Should I have the transmission pulled and rebuilt?...
What does the shop recommend?

Last edited by Easy Mike; Aug 31, 2016 at 04:21 PM.
Reply
Old Aug 31, 2016 | 06:41 PM
  #4  
Bhebert449's Avatar
Bhebert449
Thread Starter
Pro
 
Joined: May 2013
Posts: 570
Likes: 22
Default

Originally Posted by Easy Mike
What does the shop recommend?
they don't work on transmissions so they recommend I take to a transmission shop. I think I'll just live with it for a while. It' does not affect the drivability of the car much.
Reply

Get notified of new replies

To Clunk when downshifting



Thread Tools
Search this Thread

All times are GMT -4. The time now is 04:52 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 11:09:53


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