Hey everybody,

I have a 2005 4WD Blazer, automatic transmission. My tranny started shifting a little bit rough and the fluid was starting to look a little burnt so today I changed the fluid and filter. Went pretty smooth, the hardest part was getting the pan on and off with the frame crossmember and exauhst in the way. I don't think I bumped or damaged anything.

Either way I added 3.5 quarts of ATF, turned on the engine and let it run for 1 min or so. Then stood on the brake and slowly shifted through all the gears. Turned off the vehicle and checked AtF level, added a bit then turned on the Blazer again. This time the CEL came on instantly so I shut it off immediately. The following codes were thrown:
P 0740 - torque converter solenoid circuit
P 0753 - shift solenoid A electrical
P 2761 - torque converter pressure control solenoid control circuit/open
P 0785 - shift timing solenoid "A"

Also, the key won't leave the ignition as if I was trying to take it out while in drive, but the tranny is in park.

 

did you damage the wiring harness to the trans or it's internal wires?

 

Just going out on a limb but I'm guessing that your problem is because it takes more like 7qts for a filter change.

 

the 4l60e recommends 5 qts with a filter change, it all depends on how long it stayed open. Sitting in the driveway and getting a Torque converter clutch code has to be electrical. Also the key wont come out unless the trans is in park, idk if the neutral saftey is part of the column or the trans. It would make sense if it was the part of the trans

 

Check all the connections on the trans. you may bump them

 

Arrrrgggggg. Couldn't figure it out so I pulled off the drain pan again. There was a Solenoid hanging down that obviously got caught and was broken while slipping the pan around the crossmember to get it back on.

Still don't know why I can't pull my key out of the ignition or move the shifter.

 

Is your foot depressing the brake peddle? I know dumb question but you never know

 

So many problems that sound unrelated...the ignition wasn't holding the key before? because that sounds like the shifter assembly is worn and not letting the shifter go all the way into park. All this from a transmission fluid change? Yikes.

There's more suggestions here

https://blazerforum.com/forum/2nd-ge...gnition-54411/