1994 Mercury Marquis Erratic Shifting

1994 MERCURY MARQUIS
18,733 MILES • V8 • 2WD • AUTOMATIC
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JAZZYMARQUI
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After about 15 minutes of driving the car starts erratically jumping in and out of gears. This problem seems to start after the car warms up.
The first thing I did was take it to a shop for a complete transmission service that included flushing the transmission all the way to the torque converter and replacing the fluid and filter.
This seemed to help but did not completely fix the problem. The next thing I tried was adding a 1/2 bottle of Lucas Transmission Treatment and instantly the shifting was so smooth that I almost couldn't feel it shift at all and the problem seemed to stop. After a few test drives it still shifts smoothly but the erratic shifting started again but not as severe so I added the other half of the Lucas. I still have the problem but not nearly as bad as it was at first. Before deciding that I need a new transmission or rebuild I was thinking (hoping) it might be the Shift Control solenoid? What do you think? If you think this might be the problem and it should be replaced where is it located? Any help will be greatly appreciated.
Thank You,
Jul 25, 2010 at 7:48 PM
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RASMATAZ
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Hi Jazzymarqui, Welcome to 2carpros and TY for the donation

Could be a shifting solenoid hanging up or the valve body-the shift solenoids are contained within the valve body. You can get the tranny pressure tested to find out more what's happening.
Jul 25, 2010 at 9:06 PM
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JAZZYMARQUI
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You are Welcome and thank you for you help Is the shifting solenoid located on the outside of the tranny? And if so, where do I look? Is this it?


https://www.2carpros.com/forum/automotive_pictures/501567_shift_1.jpg

Jul 26, 2010 at 3:26 PM
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RASMATAZ
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Sir, you need to drop the transmission pan fluid to get to it-its within the valve body
Jul 26, 2010 at 4:54 PM
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JAZZYMARQUI
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Sorry, I totally missed that you had already told me where it is located.
Just for the record. I understand why you would assume that I am a man but indeed I am a woman.
Thanks again for all your help. I will let you know if this was the problem.
Janet
Jul 27, 2010 at 2:41 AM
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RASMATAZ
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Do you have a check engine light when this is happening-might want to pull the computer for codes if none-could very well be the transmission converter clutch that's acting up-
Jul 29, 2010 at 6:06 PM
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JAZZYMARQUI
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My check engine light already has already been coming on after the car warms up before the transmission problem due to carbon build-up causing the egr valve to either get stuck open or stuck closed. I had planned on replacing the valve and I purchased a can of sea foam that I planned to use but have not decided if this is the correct fix or not yet. Don't want to make the problem worse. I did not get to do this before the tranny started acting up. I thought it should be addressed first.
I will run another computer scan to see if any new codes come up. I had planned on this already but it takes two people with my car, one to watch and count the number of flashes and one to write them down. I don't get numbers.
I can let you know what they are if you would like to know.
Thank You so much for your help. I have spent many hours of researching and troubleshooting before I found your site.
I really appreciate what you guys do.
Jul 29, 2010 at 8:35 PM
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MERLIN2021
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Fix the EGR problem first, may also fix the shifting issues.
What exact code(s) are stored?
Jul 31, 2010 at 10:06 AM
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JAZZYMARQUI
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Really? Interesting.
The codes are as follows:
172, 176, 332, 337 & 634
Aug 1, 2010 at 3:16 AM
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MERLIN2021
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https://www.2carpros.com/forum/automotive_pictures/62217_172_2.jpg


https://www.2carpros.com/forum/automotive_pictures/62217_176_1.jpg


https://www.2carpros.com/forum/automotive_pictures/62217_332_2.jpg


https://www.2carpros.com/forum/automotive_pictures/62217_337_1.jpg


https://www.2carpros.com/forum/automotive_pictures/62217_634_1.jpg

Start with the lowest codes and work up, The egr insufficient flow is a blockage of carbon in the EGR grooves under the upper intake. go here and look at 94 town car, yours is the same, fix this, then clear KAM(keep alive memory) and retest. 176 probably means you didnt goose the gas pedal during this part of the test. http://www.lincolnsonline.com/tech/00015.html
Aug 1, 2010 at 9:24 AM