[C7Red]

Downshifting my C7 Z51 w/ paddles only when going from 3-2 or 2-1 and slowing from about 30 mph to stop, a large jerk is experienced just as you would expect if the R's are not matched. Didn't seem to do this when new... just passed 7,000 mi. and the dealer had replaced the Torque Tube at about 800 mi. ago. Not sure this is related, but...

Anyone experiencing the same, or any thoughts on why this is happening?

 

[jsvette]

Welcome to our forum C7 Red! Were you basically coasting down (for example to a light) when you then used your paddles to downshift or were you in M and using your paddles all the time? If you were in D and coasting before using your paddles your engine was probably in V4 and then you downshifted which would at the same time cause it to go back into V8 and feel more jarring than if you were in M and downshifting.

 

[C7Red]

Good thought... I'm using paddles all the time, so V4 isn't involved. This "out-of-sync" jerk happens when down-shifting from either 3-2, or 2-1 and not particularly just when coasting down... meaning, you can go 3-2 just to pass when not on the freeway. Other higher gear down-shifts seem to be OK. Have you heard of "tuning" the trans?

 

[Norm]

I down shift a lot, but mainly to slow down, save some wear and tear on the brakes, and limit the dust a bit. I experienced the jerking in the 3-2, didn't even bother trying 2-1. May be just a little too much strain in the tranny at the very lowest gears. I go down to 3 and that's it. Experienced the same thing in my paddle shift '10 GS.

 

[Milliwatt Rob]

I would try to avoid any "Jerking" behavior. Remember, this is all going through your torque tube.

 

[Chip]

Good thought... I'm using paddles all the time, so V4 isn't involved. This "out-of-sync" jerk happens when down-shifting from either 3-2, or 2-1 and not particularly just when coasting down... meaning, you can go 3-2 just to pass when not on the freeway. Other higher gear down-shifts seem to be OK. Have you heard of "tuning" the trans?

There are aftermarket tranny tunes that can be had, but maybe you need to do a service shop follow up first before you explore that option. Did you have this "jerking" before the TT was replaced?

 

[mjw930]

Brake pads are a lot cheaper than clutches or torque tubes, I'm just saying........

 

[C7Red]

Thanks... no, this started after the TT was replaced. Don't know the details of an A6 auto, but if the A6 has any rev-matching capabilities just like the manual, then it's not syncing the revs for just the 3-2 and 2-1 down-shifts and causes a good jerk. Varying the speed/RPMs only effect the magnitude of the jerk. I'm heading for the Dealer...

 

[C7Red]

Right... but, I'd say normal Stingray driving shouldn't require any abnormal wear of brake pads, clutches, or TT's... do you agree?

 

[C7Red]

Agree... but, this "jerking" due to rev-matching not performing and occurs even at slower speeds where heavy engine braking is not an issue... this is a Stingray Z51 6-Speed Paddle Shift Auto (A6), you're thinking clutch modulation for the M7. Spring Mtn Singrays w/ 6-Speed Paddle Shift didn't have excessive jerking when down-shifting 3-2 and 2-1... don't think this is normal for the Stingray.

 

[C7Red]

Agree... and, I would think this "jerking" when down-shifting the Stingray is not normal behavior... scheduled Dealer Service for tomorrow!

 

[Chip]

It seems odd that your problem would begin after the TT replacement. I have to believe that your problem is related to that action, but hopefully your dealer can answer that and put things back in proper order. Keep us posted!

 

[mjw930]

Agree... and, I would think this "jerking" when down-shifting the Stingray is not normal behavior... scheduled Dealer Service for tomorrow!

No, it's not normal behavior. It sounds like the transmission control module isn't communicating with the rest of the system. I'll bet there are codes being thrown and if not then the minimum they need to do is reflash the trans and engine controllers.

 

[AFVETTE]

I routinely run up and down the gears in manual mode and the only gear change that isn't handled smoothly is the 3 to 2 all other changes to include 2 to 1 are smooth and seemless.

Regarding the 3 to 2 down shift it feels like there isn't enough "rev match" to seemlessly complete the down shift. At least that's the only way I can describe it.

 

[RCjr]

I down shift a lot, but mainly to slow down, save some wear and tear on the brakes, and limit the dust a bit. I experienced the jerking in the 3-2, didn't even bother trying 2-1. May be just a little too much strain in the tranny at the very lowest gears. I go down to 3 and that's it. Experienced the same thing in my paddle shift '10 GS.

We were always taught gears are for going, and brakes are for slowing.

 

[C7Red]

Good thought... sometimes going fast is best done when going down a gear : )

 

[C7Red]

Thanks... Dealer's contacting GM Tech for more info and will get back today : )

 

[C7Red]

Thanks... we'll see what the GM Tech says today... more later.

 

[C7Red]

Agree... my thoughts also. Dealer checking with GM Tech today for possible link with Rear Axle Service flashing on Display to this Issue... initial codes seem a bit confusing.

 

[Chip]

... Dealer checking with GM Tech today for possible link with Rear Axle Service flashing on Display to this Issue... initial codes seem a bit confusing.

That might explain the issue if your having a rear diff issue.