driving your C4 automatic
Thread Starter
Melting Slicks
Joined: Sep 2006
Posts: 3,194
Likes: 27
From: Monroe Twp, NJ
driving your C4 automatic
I have owned this car for 7 years and today for the first time I read about my transmission. It said in my manual (84) that when the car is in D it shifts and uses overdrive. Then I thought it said in 3 you get better performance. So should I drive the car in 3 for local driving with speeds under 55 or just keep it in D. Is the car faster on short spirts in 3 than D and does it hurt the transmission do drive it in 3 with speeds up to 55 on a regular basis?
Race Director
Joined: Dec 2006
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The "hurt" will only be in fuel economy if you drive in 3rd upto 55 on a regular basis. OD will also allow the torque converter to lock up giving nearly the same performance as a clutch disk against a pressure plate. With that said, IMHO, I would worry about trans temp if I didn't have a gauge installed. PeteK knows all and may chime in with his wisdom.
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
It was my understanding that while the TC could lock in 2nd-4th that it would only try to when "D" was selected. I could be wrong and don't claim to be an expert on the 84's 700r4. I hope I didn't add confusion to the topic.
Race Director
Joined: Dec 2000
Posts: 17,551
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From: El Paso Texas
When I had my 84, I left it in 3 around town, simply because it was trying to shift into and out of OD so frequently that it was annoying. It seemed like the trans was continually "hunting".
On my 95, I put it in D and forget about it. It doesn't seem to do this. Could be an electronic vs non-electronic thing.
On my 95, I put it in D and forget about it. It doesn't seem to do this. Could be an electronic vs non-electronic thing.
Le Mans Master
Joined: Feb 2011
Posts: 6,712
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From: Chatham NY
St. Jude Donor '13, '15-'16,'18 thru '25
I recall years ago hearing a conversation by a GM mechanic that if these trannys were not driven in D the tailshaft did not get properly oiled. Do I know this to be true no, but I trust the guy who did the research.
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Advanced
Joined: Nov 2011
Posts: 65
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From: Bucks County Pennsylvania
I always thought that D (3rd) was just normal everyday under 55mph and OD (4th) was for continued highway driving over 55mph.
It is annoying leaving it in OD when driving around town because it wants to shift into OD at like 40mph and it chugs when going up a hill...you need to give it a punch and force it to drop down to 3rd...
I still average 18-20 mpg around town and 28mph on the highway in OD
It is annoying leaving it in OD when driving around town because it wants to shift into OD at like 40mph and it chugs when going up a hill...you need to give it a punch and force it to drop down to 3rd...
I still average 18-20 mpg around town and 28mph on the highway in OD
Racer
Joined: Jun 2011
Posts: 315
Likes: 13
I always thought that D (3rd) was just normal everyday under 55mph and OD (4th) was for continued highway driving over 55mph.
It is annoying leaving it in OD when driving around town because it wants to shift into OD at like 40mph and it chugs when going up a hill...you need to give it a punch and force it to drop down to 3rd...
I still average 18-20 mpg around town and 28mph on the highway in OD
It is annoying leaving it in OD when driving around town because it wants to shift into OD at like 40mph and it chugs when going up a hill...you need to give it a punch and force it to drop down to 3rd...
I still average 18-20 mpg around town and 28mph on the highway in OD
In a modern car I always just put it in the highest "D" gear and it's always fine.
However, my '85 wants to be in 4th ASAP-- and is always lugging in town. I have to stomp it fairly hard to shift up, and it tends to go right back to 4th (and lugging) as soon as I lift off.
If I keep it in 3rd (non-overdrive "D") it drives much better. Thus on this car only, I use OD "D" solely on the highway (i.e., over 50 mph).
Team Owner
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Safety Car
Joined: Aug 2003
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From: Coast MS
The only reason not to use D would be if you were in a very hilly area where the transmission did a ton of unwanted shifting.
If you drive while smoothly working the gas pedal it shouldn't really matter.
If you drive while smoothly working the gas pedal it shouldn't really matter.
hahahaha...right on!
