2011 SS Automatic - Manually Downshifts on its own when stopping.

[Red2014SS]

It sounds like it's dropping into 1st gear just as you are almost stopped. It's not supposed to do that. Mine only drops to second, then drops into first after I have stopped, and begun to accelerate.

Here is a test you can do... Just as you are stopping, when you get down to about 3mph, use the paddle shift and make it go into first. Does it surge forward a little? If so, that's normal behavior. If yours is occasionally doing this on it's own, there is a problem. I've played around with the paddles a lot, and I've experienced the surge forward when you shift into first.. but only when I forced the downshift. I could see how you would fear getting into an accident. If it were my car, I'd change the fluid and filter and see if that fixes it. I've read that a lot of these L99s left the factory with the tranny about a 1/2 - 1 qt. low.

[CFD]

Originally Posted by Tiberious

Thanks all. No, I'm in D and I've lightly tapped the shifter to see if there's some way it could just be oversensitive or some physical glitch, no dice. The problem isn't so much that it downshifts, that's to be expected, it's definitely not normal though as it shifts in such a way as the car surges forward just as I'm stopping. Nothing normal about that. Also the fact that it says M1 when I am not manually shifting should make it clear that it's not a normal downshift. No aftermarket tuning, still under extended warranty. I think MrChris has it about right, but without getting the dealer to be able to repeat the problem, I'm not getting any support. My brother in law and nephew both work at GM and are looking into the issue from that end. I can't imagine that I'm the only person with this problem though. Thanks all for the feedback, while I'm disappointed that nobody knows for sure what's going on, I'm glad none of you have the same problem!

Tib

This is why it seems to be a faulty switch or TCM. The only way to get "M1,M2, etc." to display is to put it in tapshift mode which is done by tapping the switches. If you are not tapping the switches then either the TCM is receiving a faulty signal or the TCM is bad. Normally a damaged wire outside of the switches will cause no signal so tapshift won't activate or if it is activated it won't shift. I could be wrong, I'm only basing this on the info on hand, when the problem is solved I'd be interested in knowing what it is.

[Tiberious]

If the dealer cared enough to replace it, I'd be pretty pleased...but since they can't replicate it, they ignore it. Thanks Red, I'll try that next time I'm out!

Tib

[lawdog]

I talked to one of the transmission engineers of the Camaro automatics at Induanapolis. in his words, make sure you change the tranny fluid and filter at 50,000 miles !

[Indyblue98]

I have a 2007 STS-V and 2014 ATS Turbo plus a 2012 Camaro SS all of them down shift automatically when slowing.
Even in "M" or "S" modes.
Pretty sure this is what GM intends to happen.

I agree it doesn't sound like Manual Mode if it Downshifts Automatically.
But I've driven in a number of GM cars that all perform this way.

[KReef]

Any updates on this thread?I have had my car at the dealership 3 times. They cant duplicate the problem. I will be in D in residential area so i am mot goingover 35. It will downshift into M1 while in D. I am no where near touching the tapshift.I would like to add they replaced the paddle ignition switch the 1st time. The 2nd time the BCM was replaced & this last time after they drove it 100 miles for a total of 13 times over 1.5 weeks, they unhooked the paddle shift wire.

[KReef]

do you have a work order if this wa ever fixed?