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Hello and thank you for you question,Any time the traction control light comes on the computer system will set and store a fault code and or codes. In order to determine what is failing the first thing you need to do is to have the system scanned and the fault code and or codes retrieved . I suspect you are right and you may have a Speed sensor concern but to know for sure I need to know what the fault code is that is setting. If you can get the system scanned and the fault code I will help you get this resolved.
Sure thing, post back when you can with it and we can work from there.
I suspect you have a speed sensor concern and if that is the cases the system will set a fault code. You may not be able to retrieve this code with a code reader . Your going to need to have it scanned with a full scan tool. If the light is coming on there has to be a fault code.
The ABS and speed sensor are one in the same. There are 4 sensor on your 2008, one on each wheel. See the wiring diagram in the link below. Copy and paste the link to your browser to open and view them.
No it dose not, I have never sees a torque converter cause the traction control light to come on. That being said a bad converter can cause a shutter but not while breaking. Are you sure this mechanic knows what hes doing?
A failing coil can cause the engine to skip but its often more pronounced and it will usually cause the misfire monitor to pick up an engine misfire and cause the check engine light to flash plus set an engine misfire code. One thing you can have them try is to hook up there scanner and monitor the engine data stream and see if they can pick it up from there. I suspect it is a traction control problem especially if the light is coming one and I dont understand why there is no code setting. There really should be if the light is coming on.
Your right at the transition point with RPM where this could very well be a coil dropping out. If your mechanic has a good scanner he should be able to look at the misfire count with and see which cylinder it is if in fact it is an engine misfire.
A misfire would sure be the least expensive repair for sure.
It was a problem in the early days of the 5.4 but not so much now, it wild not hurt to pull the coil on that cylinder which is the worse one to access and see if there are any signs on coolant on the boot. Nothing left to loose by at least looking.
I would not replace all the coils, I would look at the misfire count and see if its showing a misfire and if so replace the coil on the cylinder that showing a miss. Flushing the transmission would likely be a waste of your money. If it fact it was the torque converter causing the shudder a flush would not help.
Glad to hear your making progress and thing are working better.