Hard shifts automatic transmission 87 C4
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6th Gear
Joined: Apr 2021
Posts: 6
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Hard shifts automatic transmission 87 C4
Hi all,
I bought my first Corvette (1987 C4 Conv.) last year. I am from Europe and the first owner in Europe (2 owners in the US). The car only has 14k miles and still was on original tires. I had all the fluids and filters changed + new tires. The car is completely stock, is in like new condition and has always been cared for.
My question: The car shifts hard from 1 to 2, 3rd and OD are rather smooth but still noticeable. Both upshifts and downshifts. Every other shift I hear a clunking noise, mostly downshifts. Is this normal for these transmissions? I have a "7YDM" transmission.
All the other American cars I had shifted extremely smooth I didn't even notice a gear change.
Thank you in advance for your highly appreciated expertise.
Michael
I bought my first Corvette (1987 C4 Conv.) last year. I am from Europe and the first owner in Europe (2 owners in the US). The car only has 14k miles and still was on original tires. I had all the fluids and filters changed + new tires. The car is completely stock, is in like new condition and has always been cared for.
My question: The car shifts hard from 1 to 2, 3rd and OD are rather smooth but still noticeable. Both upshifts and downshifts. Every other shift I hear a clunking noise, mostly downshifts. Is this normal for these transmissions? I have a "7YDM" transmission.
All the other American cars I had shifted extremely smooth I didn't even notice a gear change.
Thank you in advance for your highly appreciated expertise.
Michael
Melting Slicks
Joined: Feb 2003
Posts: 2,685
Likes: 814
From: Saskatoon Sask.
Hi all,
I bought my first Corvette (1987 C4 Conv.) last year. I am from Europe and the first owner in Europe (2 owners in the US). The car only has 14k miles and still was on original tires. I had all the fluids and filters changed + new tires. The car is completely stock, is in like new condition and has always been cared for.
My question: The car shifts hard from 1 to 2, 3rd and OD are rather smooth but still noticeable. Both upshifts and downshifts. Every other shift I hear a clunking noise, mostly downshifts. Is this normal for these transmissions? I have a "7YDM" transmission.
All the other American cars I had shifted extremely smooth I didn't even notice a gear change.
Thank you in advance for your highly appreciated expertise.
Michael
I bought my first Corvette (1987 C4 Conv.) last year. I am from Europe and the first owner in Europe (2 owners in the US). The car only has 14k miles and still was on original tires. I had all the fluids and filters changed + new tires. The car is completely stock, is in like new condition and has always been cared for.
My question: The car shifts hard from 1 to 2, 3rd and OD are rather smooth but still noticeable. Both upshifts and downshifts. Every other shift I hear a clunking noise, mostly downshifts. Is this normal for these transmissions? I have a "7YDM" transmission.
All the other American cars I had shifted extremely smooth I didn't even notice a gear change.
Thank you in advance for your highly appreciated expertise.
Michael
Not normal and the very first thing you have to do is properly adjust the TV cable at the throttle linkage. There is a multitude of information on the internet as to how to do this correctly.
Art Carr's 700r4 tv cable adjustment guide from CPTtransmission.com
