When I drove it this afternoon, something strange happened to my car. When I released the brake after the traffic changed to green, I heard a sound "BONG" and then I found the car cannot accelerate. It ran just like i didn't give gas. Late I found that the "R", works well. I still can drive the car like I don't have a AT but a stick one. I started from 1. When the speed reached 5 mph, I shift the handle to position "2". When the speed reached 15mph, I shift the handle to position "d". After the speed reached 25mph, I shift the handle to position "D" and then I can drive the car at speed from 30-40mph. I have not tried at higher speed. Anyone can help me point out what is the problem? Thanks

Start with the basics and then some of the Transmission Gearheads will chime in. Have you ever changed the xmission oil on this car? Have you checked the xmission oil level? Is the color of the xmission oil bright red? Brown?? Black???

Good advice from Ol'Timer. Check the cheap stuff first. Yours are the same symptoms my '95 had when I bought it. I was able to drive it by shifting it manually, but it would not downshift on its own and got rougher and rougher. I took it to a trans shop for a free diagnosis. The guy said I had a broken sprag assembly.

I built an engine hanger;
http://www.bonnevilleclub.com/forum/...ic.php?t=29081

bought a used trans from a junkyard; removed the old trans;
http://bonnevilleclub.com/forum/viewtopic.php?t=28558

and installed the "new" one.
http://bonnevilleclub.com/forum/viewtopic.php?t=29367

Maybe you will have better luck and just need to add some fluid.

I have not changed the transmission oil. I checked the oil today. It is like light brown. I found the oil level is much higher than the max level. I have no idea how this happened, but perhaps it was the jiffy lube guy added some oil when I changed the lube couple weeks ago. Can this be a problem? Thanks

One symptom of mine that is some different is that it can downshift automatically when I step the break.

Really appreciate bill buttermore and Ol Timer'* advice. Thank you very much.

Yes, it could. I would get the extra oil out of there. A first try at a cheap fix would be to drop the pan, clean it, change the filter and top it up to the proper level with new Dexron III. This will only cost you about $25 if you do it yourself. Jiffy-Lube has a well-deserved reputation for cheating people and for screwing things up. Find a trusted shop if you can not do your own work.

One other thing I did not mention, nor did I hear from anyone else. When you check the transmission oil, make sure the engine is hot and the the transmission is in Park. If the xmission oil is not hot it could give you a false level reading.

The trans temp will not change the color of the oil, just the level

Change that fluid!