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Discussion Starter #1
I was wondering if someone could direct me to the proper location in the prior posts and threads, or give some advice on this problem.

I have a 1995 Deville, 100K miles. My transmission appears to work fine but with the following issues.

When I am stopped at a stoplight or stopped for any reason, when I go to accelerate from that stop the engine revs for about half a second then "slams" or "thunks" into gear. This only happens when I am stopped and there dont appear to be any other issues from the other gears. My transmission fluid level appears to be fine. What can cause this? I have been reading through the archives and I am not clear if I should work on getting a new transmission or work on my shift solenoids. Thanks for your advice in advance

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The only reason I know anything about the 4t80e is I just had mine rebuilt for doing the same thing. Do you have troubles shifting into O.D. as well. I found out that it was my clutch. I hope you had better luck than I did. It cost me 1600 to fix.
 

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the 94-95 devilles have a tendancy to break the engine mount thats right by the A/C compressor ...witht he hood up start the engine and put it in reverse and "brake torque" it , see how far the engine comes up , if you say "holy crap im suprised it hasnt gone thru my hood" then , most likely its bad ....do the same in forard to check the other set ....

the mount by the A/C compressor is fairly easy to swap and costs around 70 bucks at your local autoparts store
 

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Discussion Starter #6 (Edited)
Stoneage_Caddy said:
the 94-95 devilles have a tendancy to break the engine mount thats right by the A/C compressor ...witht he hood up start the engine and put it in reverse and "brake torque" it , see how far the engine comes up , if you say "holy crap im suprised it hasnt gone thru my hood" then , most likely its bad ....do the same in forard to check the other set ....
the mount by the A/C compressor is fairly easy to swap and costs around 70 bucks at your local autoparts store
Thanks!! I will try this when I get home from work today, and if it displays that behavior, I will get them changed this weekend. I hope this is what is wrong with it.
 

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Discussion Starter #8
Mini update.

Last night I checked my codes and they were:

P031 -Shorted MAP Sensor
P065 -Cruise - SPS Failure
P098 - High RPM P/N to D/R Shift Under ISC
NO IPC
A037 -Loss of Instrument Panel Cluster Data
No SIR
NO TCS
PCM?

What are some ideas on what was displayed?
Should I have continued on the the PCM? test?

Thanks for your advice and opinions in advance
 

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How do you read your DTC codes?

Sorry can't be of any help, but I just had my shift solenoids replaced for a similar problem and now my baby is runing fine.
 

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Discussion Starter #11
Update:
I finally got my car into a mechanic for a "diagnosis" and here is what he told me almost verbatum.

"There is nothing wrong with your trans, motor mounts, or shift solenoids. There are cars that come off of the assembly line that dont shift as well as yours. I would hate to charge you a lot of money and then have you STILL have the same problems. I know people who have wasted money on such problems. I KNOW your motor mounts arent bad. There might be a SLIGHT problem with your solenoids but nothing major"

After this I was perplexed. So immediately went home and had my neighbor take the car for a spin around the block without telling him that ANYTHING was wrong . When he got back he said.

"Damn dude, thats a nice riding car. And clean too. However, when I was at the stop sign down the street, it seemed like your transmission "popped" then i went to take off from the stop sign. Other than that it rides fine."

So I get up this morning and decided to drive it to work because I figured maybe I was being too picky. It was kinda cold outside this morning and when i went to put it in drive then it didnt move when I pressed on the gas. I had to put the car back in park , then put it in drive again before I could pull out of the driveway.

Again, on my way to work i experienced the same "thunking, popping" whenever I stopped at a stop sign or had to stop in traffic.

When I went on my lunch break, i experience the same behavior that happened in the morning. I went to put it in drive then it didnt move when I pressed on the gas. I had to put the car back in park , then put it in drive again before I could pull out of the parking lot.

After lunch I called the guy (mechanic) again and he said that it sounded like a bad sensor.

Any opinions?
 

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How long have you had the car? How long has the trans acted like this?

Have the fluid changed (not flushed). It's easy if you want to do it yourself. The gasket is reuseable and there is no paper filter. There are screens to catch debris.


Test the MAP sensor. Make sure it isn't a shorted wire in the harness. It tells the engine what the air pressure is, which the computer uses to adjust the injector pulse.
 
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