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1986 Automatic Transmission Problem

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Old 10-28-2007, 01:09 AM   #1
Bogdan
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Default 1986 Automatic Transmission Problem

While in drive, my engine began to rev over 4000 rpm without delivering any response from my transmission. When I managed to get the car home I noticed a fine film of oil on the entire back of the car. The next morning I saw oil underneath the car on the passenger side and as far back as the new muffler on the passenger side only.

The day this problem started I had just installed a new stainless steel high flow catalytic convertor, y-pipe and mufflers from MagnaFlow. Great sound, improved horsepower and torque as they promise. But now the question, could the extra force from the new exhaust system cause the transmission to either blow a gasket or break a line causing my problem? Or could it just be age and coiincidental?
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Old 10-28-2007, 01:44 AM   #2
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Did you fiddle with the transmission or the lines at all? Where is the level of fluid? What does it look like? How does it smell? How far did you run it in this condition?

I'd say it's time to get the car in the air and start finding out where the leak is coming from.

I can rebuild a transmission, but I'm not good at troubleshooting over a distance and generally just systematically trace the problem versus knowing that 'yep, that there might be your problem.' PeteK is an excellent, knowledgeable forum member who will more than likely chime in this thread.
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Old 10-28-2007, 09:57 AM   #3
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tranny line leak there are some hard lines down thre on passenger side. i have a 86 and it leaked like a sieve. tranny wont shift properly without fluid as far as i know..
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Old 10-28-2007, 01:45 PM   #4
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Thanks for your response. I checked the fluid level and it is down but not dry. The color is pinkish brown but that is the color I think it was when I had the car serviced three months ago. It does not smell burned but not sure. I drove it about 5 to 7 miles to get home. I did not tamper with the lines and still need to get the car in the air to have a good look. It may be that a line got damaged at the muffler shop and did not show up until the oil level dropped. Hopeful for that. Or the gasket blew under pressure. Otherwise, plan on flushing the transmission, changing the filter, and new gasket tomorrow. For now, just going to top it off and see if the trans works right for awhile to rule out anything worse than low oil level.
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Old 10-28-2007, 01:46 PM   #5
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Thanks for your info. I plan on checking the lines tomorrow morning at a shop.
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Old 10-28-2007, 04:55 PM   #6
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I just want to bounce this off of you before tomorrow. I just went under the car and it looks like the leak came from a blown gasket on the trans pan. I ran the engine to get it to normal operating temperature and then checked the trans fluid level. I topped it off with about 8 ounces of fluid. Next I went to test drive the car and found that the shifter moved a little stiffer between P and R, P and D, but the transmission shifted smoother than before. Whether in R or D, I had to get the car up to 2000 RPM in order for it to move forward of backward. Any ideas on how bad it might be? If required, is it better to go with a new transmission, rebuilt trans or have someone rebuild my transmission?
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Old 10-28-2007, 05:31 PM   #7
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See if they can rebuild it -- most likely they can. I had the tranny in my '86 rebuilt a few weeks ago.

I was driving it the one day, and stopped at a light. Went to go, and the car drove normally -- minus a clunk when I hit the gas. Thought it was awkward, but it still drove fine. A couple minutes later -- after a quick stop to drop the passenger off, I went to accelerate and it was real sluggish. Limped the car the 3 miles home, literally, limped it.

Multiple things ended up being wrong in my tranny, the car is absolutely spectacular now.
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Old 10-29-2007, 03:45 AM   #8
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Thanks for the information. That is what happened to my vette as well. Plan on having it towed tomorrow and rebuilt if required. Will let everyone know the answer tomorrow on the problem and the solution.
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Old 10-29-2007, 01:03 PM   #9
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Can you tell me what was wrong with your trans and how much they charged to get your vette back up and running?

I just had mine towed to a trans shop and waiting to get the call on how bad it is. They told me it might cost up to $1200 and take three days if it requires a rebuild.

When they rebuilt your trans did they rebuild it to factory specs or did you have them do anything special, i.e. different stall level?
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Old 11-05-2007, 12:27 PM   #10
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Default Transmission Problem Solved

Just wanted to thank all of you for sending me a reply. I just got the car back and it is running great!

The problem was nothing that I or anyone who drives an 86 Vette with that tranny could be responsible for no matter how you drive. The torque convertor failed inside the tranny. Apparently, a weld on the inside of the torque convertor just broke loose or wore out. This left the transmission with no power to the drive train as it just would not spin. The tranny fluid that ended up on the underside of my car and on the back as a fine mist was a result of the tranny overheating and then blowing a seal (which it is designed to do) on the passenger side to let you know you have a problem.

Total cost to overhaul and rebuild it was $1,600 including the $50 tow.

Lesson learned: No matter how much we take care of our Vettes with routine maintenance things like this can and will happen through no fault of our own.

Thanks again for your advice earlier. Pass this along if you hear of others with similar problems.
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