This is on an '11 Colorado, I5, 4WD, about 235,000. The truck generally drives really well, but I have one or possibly two issues that may or may not be related. I'm hoping that some of you with more experience can help me out with that.
I've started having a random electrical issue (I think.) About three months ago I suddenly had developed a rough gear shift (automatic). Scanned it, and returned 2 pendings and 1 current (that was the same as the pending). P0700 Powertrain "Transmission Control System (MIL Request), and U0073-Network. The 73 showed as both current and pending (I use a basic wireless scanner and Torque.) So, I did the basic DIY type of thing that I would know to do. These trucks are known to have a potential grounding issues, so checked all of those that I was aware of, and cleaned the contacts on the TCM and the sensor on the transmission, checked every fuse, checked for voltage loss, etc (basic troubleshooting)... Problem went away.
When it happens, it seems/feels like the transmission is going through a relearn process. After about 4 harder shifts, it calms down and drives as good as it ever has since I got it about three years ago. And, it may go three weeks between happening, but it's popped up about four or five times overall.
Fast-forward to a couple of days ago, and I had to brake kind of hard while turning on a bumpy road. But I also heard a weird but familiar "boing" noise (ABS?), and the issue came up ('fixed' itself within like 2 minutes'). As far as I can remember, this is the only time that I've ever heard it other than close to startup (next paragraph). The ABS usually just kind of acts and sounds like an ABS usually does.
Now, this same noise is something that I've heard off an on since I got the thing. It happens mostly on cold startups, and basically corresponds with the first initial shift. I've read that it's possibly the ABS test, but it doesn't seem to be exactly as others have described. If I go into a store for an hour (cooling off) it may or may not do it again, but for a quick in-and-out somewhere it won't. I honestly don't even know that this is even an 'issue' that needs addressing, but since it corresponded with the fault this last time, I wanted to include all of the info that I could.
So, I'm not completely ignorant of basic electrical stuff, but I don't know enough on my own to do any crazy advanced diagnostics. I can bring it somewhere if I have to, but obviously that's not my first choice, in part because I realize how hard this intermittent issue could be for anyone to find. So my basic questions are:
- Is there some area or thing that I should be looking for that I don't even know about? - Would saying screw it and taking it to a shop, who would have a Tech 2 available, just be the best thing (or would they likely have problems finding it, also.) - And, what is this sound, and is it even probably related?
The video is of the noise. Ignore the blinker, but it basically happens around the same time as the third blink.
I would def appreciate any insight or guidance. Thanks!
Topic Author
