car issues

I have an 03 trailblazer ext, actually my wifes, that was seeming to start off the line more sluggish than normal. 61k miles on it, 4x4, v6. Well i was just about to do a tune up on it when i was driving up a hill and it downshifted as normal but wouldnt up shift anymore. I checked the fluids and all seemed normal and after reading about the sunshell thought it might be that. Also read they have a problem with losing 3rd gear. well i have 1 and 2 only so i thought it could be that. After taking to a family friends trans shop we hooked it up to the scanner and pulled a U1301 code. Its a communications for class 2 data. The trans info on the scanner didnt show in actuall info from the trans, not current gear, speed ration, soelinoid on/off for any gears. Before we hooked the scanner up i saw my car charger didnt work. We hooked up the scanner and got no power. replace the cigar fuse under the dash and the aux power fuse under the rear seat all other fuses were fine. Question is where to start besides tracing wires im in the process of doing that. I talked to shops my family friend recommended but they wont be able to get to it for about 2 weeks. Is there anything i can do with basic tools(multi meter tester and similar tools, Got all wrenches too). Thanks in advance,
Eric

Do you have reverse? Typically when the sunshell goes you lose reverse and another forward gear.....I think 2nd. Is it a genuine slip condition? Tach goes up but no forward momentum? There are horror stories on this & other forums regarding the sunshell. Of course you have checked the fluid, but does it smell burned? I would drop the pan, check for metal shavings & try to get as much fluid out of it as possible, then replace fluid & screen. There are good pump out proceedures on here as I'm told there is no convertor drain on these...go figure. As far as I have read, with sunshell failures, you get tranny specific codes. These prolly can only be read by an OBD II scan, and your SES light may or may not be on. I know these 4L60Es we have in our trucks are also in the the vettes...with bigger servos of course, so they have to be stout. On the other hand I have read where the sunshells are made out of an inferior metal. I do know heat kills trannys and the "recommended" tranny service in your owners manual is garbage. Keep us posted what you find out & good luck.

well after digging deeper and a different scanner all electronics are working fine. show the tranny is shifting but it isnt. Pan was dropped and metal shavings were in it. It appears the clutch pack dropped 3rd and 4th. Add another tranny death to the trailblazer at 61K. rediculous that this is a known problem and they last just over 50k miles. tranny shops here are all too familiar with them. 1800 bucks later and we will see if it works.