I have the SUV listed above with 4L60e. The transmission was shot when I bought it and I knew that. I also have a 1998 Yukon identical in every way. I took transmission from 1998 which worked perfectly and put it in the 1999, since doing so I have no first or fourth gear. Obdll scan doesn't even recognize the transmission is missing the 1-2 shift only kicks a code for bad 2-3 shift which I have to do manually. I understand first and fourth are electronically controlled so I assumed electrical problem. Checked all fuses, checked #13 pin on TCM for voltage, ohm reading on A and B solenoid, ran and erased codes, replaced TCM plug with original one from the bad 1999 transmission including all solenoid wiring. I know there were some ignition issues causing shift problems during the period for GM I'm not getting the codes that indicate bad ignition though. I am completely out of ideas and I can't lay under this thing any longer or watch another YouTube video. I need help. I am no mechanic or claim to be, I paid a so called mechanic to put transmission in and I've been left to deal with this. I know I should've taken it to a reputable shop but I chose to save some money and earned a huge pain in the butt. It has now became personal! Does anyone have any suggestions as to what I should do? I've read that transmissions and TCM are VIN specific they can't be swapped without flashing the computer? Any advise will be greatly appreciated.
Mar 14, 2019 at 12:12 AM
