mild, intermittent, "clunk" on the final down shift
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Race Director
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mild, intermittent, "clunk" on the final down shift
i'm getting a very mild, intermittent, "clunk" on the final down shift (e.g., when slowing down - comming up to a red light or stop sign - the final downshift into low) on my (new to me) 90 w/ A4 trans. i'm sort of suspecting a u-joint, but until i get under the car, i'm just guessing. comments on what and where i should start looking. i've only had this car for a week or so, and i can't recall hearing anything on the test drive. funny noises doesn't give me a warm and fuzzy...
comments, and TIA -
comments, and TIA -
Last edited by Joe C; Aug 12, 2008 at 10:24 AM.
Melting Slicks
Joined: Nov 2002
Posts: 2,471
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From: 1993 Quasar Blue 'vert Scottsdale AZ
Does it make a difference whether the tranny is in drive or overdrive when this happens? Mine will clunk when downshifting into first from drive, but not when downshifting from OD.
Team Owner
Joined: Dec 2000
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From: Phila., PA burbs
Thread Starter
Race Director
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the "clunk" is in OD - haven't tried it driving in D, but that's food for thought. it seems like it could be a tranny issue - ???, but i still want to go through and check the rest of the drivetrain. thanks for the replies so far...
Thread Starter
Race Director
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Thread Starter
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
went out for a test dirve. much, much worse in D than OD. i googled "downshift clunk 700r4" and found several sites that refer to a transgo kit #SK-700 - supposed to eliminate downshift ckunk. anyone out there use one of these kits? ...still not totally convinced it's not a u-joint though.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
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From: Tampa Florida
went out for a test dirve. much, much worse in D than OD. i googled "downshift clunk 700r4" and found several sites that refer to a transgo kit #SK-700 - supposed to eliminate downshift ckunk. anyone out there use one of these kits? ...still not totally convinced it's not a u-joint though.
Good Luck!
LS/MFT
Joined: Jun 2000
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From: Cary IL
St. Jude Donor '09-'10-'11-'12
Chevy issued TSB 91-372-7A in July 1991 "3-2 Coastdown Clunk"
"Some 1990 and 1991 Chevrolet Corvettes may experience a 3-2 coastdown clunk. The clunk is felt around 10-14 miles perhour while lightly braking to a stop. It is most noticeable in D3 range but may occur in D4 (overdrive) range.
A new 2-4 servo cushion assist spring and spacer plate have been released to alleviate this condition ...."
Talk to your local Chevy dealer about getting the "Corvette 3-2 Improvement Package" referenced in the TSB.
Jac
"Some 1990 and 1991 Chevrolet Corvettes may experience a 3-2 coastdown clunk. The clunk is felt around 10-14 miles perhour while lightly braking to a stop. It is most noticeable in D3 range but may occur in D4 (overdrive) range.
A new 2-4 servo cushion assist spring and spacer plate have been released to alleviate this condition ...."
Talk to your local Chevy dealer about getting the "Corvette 3-2 Improvement Package" referenced in the TSB.
Jac
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Melting Slicks
Joined: Nov 2002
Posts: 2,471
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From: 1993 Quasar Blue 'vert Scottsdale AZ
I never noticed this until I had the tranny rebuilt with a B&M shift kit. I experimented this morning and the clunk is much lighter then it used to be. Has your tranny been rebuilt? Maybe a shift kit installed.
Team Owner
Joined: Oct 2004
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Thread Starter
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
Chevy issued TSB 91-372-7A in July 1991 "3-2 Coastdown Clunk"
"Some 1990 and 1991 Chevrolet Corvettes may experience a 3-2 coastdown clunk. The clunk is felt around 10-14 miles perhour while lightly braking to a stop. It is most noticeable in D3 range but may occur in D4 (overdrive) range.
A new 2-4 servo cushion assist spring and spacer plate have been released to alleviate this condition ...."
Talk to your local Chevy dealer about getting the "Corvette 3-2 Improvement Package" referenced in the TSB.
Jac
"Some 1990 and 1991 Chevrolet Corvettes may experience a 3-2 coastdown clunk. The clunk is felt around 10-14 miles perhour while lightly braking to a stop. It is most noticeable in D3 range but may occur in D4 (overdrive) range.
A new 2-4 servo cushion assist spring and spacer plate have been released to alleviate this condition ...."
Talk to your local Chevy dealer about getting the "Corvette 3-2 Improvement Package" referenced in the TSB.
Jac
Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
I had my trans rebuilt and a transgo shift kit installed about 20k miles ago and it stills clunks same as before.
