Overdrive performance
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Navigator
Joined: Aug 2009
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Overdrive performance
I bought my first Corvette about a month ago. I purchased a 1986 convertible with 39,000 miles on it. I decided to take it out on the road this weekend. The automatic transmission shifts into overdrive at about 67 miles an hour. If you drop below 66 it will downshift. Is this normal for this car/transmission? It drives sweet and everything operates fantastic, just found it a little odd that it does not shift to overdrive until at that high a speed. Also, what is normal for a couple of hour trip for the oil temp to run at? Mine was running at about 218 with the AC going in 90 degree heat. I would consider this normal, but wanted some input from others who own a C4. Thanks
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
I'll start, 67 is too high. Obvious question is "Where do the other shifts occur? Suggest you do two very simple things, check your transmission fluid level, adjust your TV cable. A search will produce detailed instructions for TV cable adjustment. Your temps are correct.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
http://forums.corvetteforum.com/1571150481-post8.html
http://forums.corvetteforum.com/c4-t...le-adjust.html
Stabilized oil temps are typically 15 - 20 degrees above engine temp.
http://forums.corvetteforum.com/c4-t...le-adjust.html
Stabilized oil temps are typically 15 - 20 degrees above engine temp.
Thread Starter
Navigator
Joined: Aug 2009
Posts: 9
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Thanks to all, you headed me in the right direction. The tranny is also shifting between first and second too quickly. After reading your posts I found this helpful link on adjusting the TV cable ona turbo 350.
http://www.tciauto.com/Products/Inst...ble_adjust.htm
http://www.tciauto.com/Products/Inst...ble_adjust.htm
Thread Starter
Navigator
Joined: Aug 2009
Posts: 9
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Followed the procedure for adjusting the TV cable. It now shifts 1-2 at about 16-18, 2-3 at about 25-27, and 3-OD at about 45-49 all depending on how deep I get into the throttle. Thanks again for aiming me in the right direction.
Burning Brakes
Joined: Aug 2001
Posts: 1,146
Likes: 9
From: Troy Ohio
I bought my first Corvette about a month ago. I purchased a 1986 convertible with 39,000 miles on it. I decided to take it out on the road this weekend. The automatic transmission shifts into overdrive at about 67 miles an hour. If you drop below 66 it will downshift. Is this normal for this car/transmission? It drives sweet and everything operates fantastic, just found it a little odd that it does not shift to overdrive until at that high a speed. Also, what is normal for a couple of hour trip for the oil temp to run at? Mine was running at about 218 with the AC going in 90 degree heat. I would consider this normal, but wanted some input from others who own a C4. Thanks
