Cadillac Repair: !!!, cadillac sedan deville, service engine soon light

Question
Hi,

   I have a 1995 cadillac sedan deville. It now has 155k but I bought it with 65k. It has really been a reliable car. Recently I had to have the transmission replaced (rebuilt). I have driven it for 2000 miles since having it replaced, now the service engine soon light comes on. The only time it seems to come on is when I am going 50 miles an hour and it does not come on at higher speeds. I have taken the car back to the transmission place   3 times now thinking the problem is corrected and they can't seem to get it right! What is going on with it? It still seems to shift wonderfully. Any help would be greatly appreciated. The code showing in the computer is po39 and that is the only one in it.

Thanks so much                                      ! jay

Answer
P039 is a fault within the over drive circuit for the transmission.

diagnostics consists of 10 pages of pictures and test procedures that are not that difficult to do. If you are mechanically inclined we can find and fix this problem if you contact me at: onlineautohelp@msn.com

tom