Problems one after another

[Alfonso Gomez]

OK, here's how it goes: 1987 coupe with auto tranny and 3:07 gears, daily driver.

First, since my gas mileage is so lousy (13 mpg city) I decided to change the Oxigen sensor, which I suspected had not beeen changed ever. Piece of cake. The old one was an AC Delco and it looked pretty dirty. Replaced it with a Bosch.

Then I noticed that the alternator was not charging properly, especially with the A/C and headlight on. Took it out, had it checked and replaced with a new one. It was charging 10 volts in the bench tester. Also took the battery (18 months old) for a recharge.

Then found a leak in the cooling system because one of the coolant lines that go to the oil cooler was damaged. So I replaced it. Easy.

While driving to the local Pep Boys shop to have the electric system checked (I felt it was not completely right), I noticed that the transmission would not shift from second to third. Then I stopped at a traffic light and when I took off, the transmission woul not shift into second gear. Had the electrical system checked and found that the new alternator had problems with the voltage regulator.

Drove back home and the transmission would not shift into second gear. Stopped to check fluid level and found it one quart low. Put in a quart of fluid and started to drive home in first gear. I tried the following while driving in first gear: at about 23 mph, I let go ef the gas pedal for about 10 seconds and when I accelerated the car had shifted to second gear

. It stayed in second gear even after stopping at a few other traffic lights. It took off in second gear but would not shift into third gear.

Sorry for the long post but right now I'm waiting for the engine to cool off before removing the alternator and taking it in for a replacement.

After I replace the alternator I have to tackle the tranny problem but I would like to know if there is something I have to check before taking it to a shop.

Thanks for your help.

 

[Vette_Newb2]

If I remember right, the tranny is an electronic shift. Since the tranny problem arrived with the installation of a new alternator that was not working properly it could possibly have an affect on the shifting. I am not completely sure, but when it coincides that close with the alternator problem I would suspect it.

How many miles are on the car? Have you had any trans service performed?

 

[Hib Halverson]

87s do not have electronically controlled automatics so the alternator issues you've had should not affect transmission shifting.

If you are going to tackle the trans problem on a DIY basis, you need the factory service manual for its troubleshooting information. If you lack the book or the automatic trans experience, I'd take it to a transmission specialist.

if this is also a car with a lot of miles and it has been run low on fluid, you might be looking at an overhaul.

 

[brookman]

Welcome to the used/not well maintained corvette world. My 88 had a lot of the same problems you are dealing with when I got it. It seemed like one thing after another was going wrong with it.


Did you mess with the transmission cable that connects to the throttle plate on the intake? That adjustment is critical to the proper shifting of the 700r4.

I do know for a fact that these transmissions do not like it when the fluid is low and will not shift correctly if it is low.

You said it was a quart low. Is there transmission fluid on your driveway or garage floor? If there isn't - when it cools down - take the cap off of your radiator and see if the anti-freeze has a red tint or milky look to it. The only other place fluid can disappear is in the cooling loop in the radiator.

 

[OLDCHEV]

If this is not an electronic transmission the vacuum modulator is bad or the vacuum hose is disconnected or broken. That is why it will shift into second from first while coasting above 20 mph.

 

[brookman]

The 700r4 is not vacuum controlled . The TV cable is what sets the line pressure to determine shift points and uses the govenor to determine which gear to be in.

 

[Alfonso Gomez]

The 700r4 is not vacuum controlled . The TV cable is what sets the line pressure to determine shift points and uses the govenor to determine which gear to be in.

Adjusted the cable as per instructions found elsewhere and it would only shift at WOT. It chirped the tires going from first to second :L but i can't drive WOT all the time. So I adjusted it again and now it works fine. Thanks, guys.