Rd16rr

2015 A8 convertible 17,000 miles (2 flex plates, 1 rear diff replaced) currently waiting for GM to respond to excessive oil consumption (1qt every 500miles) - could the shudder be related to the torque converter (if we have one) ?

I'm getting a shudder type vibration at varying speeds - at first I thought I lost a wheel weight (tires were replaced recently) but they are all present - then I thought maybe it was the road surface at different parts of my ride - then I was thinking the wind together with the rear spoiler, front splitter & winglets were messing with me....but after tonight's ride, it seemed to get a bit more agressive - it occurs while "at speed" not under acceleration per say, other than what would be normal for going up thru the gears (shifting 3500 to 4000 rpm's)...while just moving along, at near 50 to 80...then it simply disappears which is what originally had me think it was road surface....anyone with anything to share...?

owc6

Does it happen only at certain speeds, or is it related to acceleration or deceleration or RPMs?

Does it happen in a cyclic way? Meaning does it give you a bunch of shudders, then a pause, then a bunch and repeat?

ratboyusn

Yep, I am experiencing the very same symptomolgy. Happens more 'at speed' and especially noticeable in cruise control. Took it in to the dealer and the tech acknowledges the problem... there are at least two bulletins (one posted on this forum from Jan 2016) and an updated version from March 2016 (I haven't been able to locate, but dealer states they have it).

It will likely result in the replacement of the torque converter and transmission fluid (at a minimum). Will update as repairs are made on what was done and if the ride improves.

I'm at 4900 mi and have the A8 tranny, 2015 Z-51, BTW.

BRONCOSRUL

I know exactly what it is. Had the same issue at 2300 miles on a 2015 Z51 A8. At first dealer tried to tell me it was the active fuel management turning on and cutting off after a one mile test drive. Went and drove the car with the foreman. The look on his face was classic when the shuddering began. It is a bad torque converter. Torque converter was replaced, 12 new quarts of transmission fluid and a new transmission fluid filter put in. Took a week to complete. All under warranty and they were nice enough to get me a Chevy Traverse rental at no cost. Don't lose sleep over it.

Rd16rr

...nice ! Thanks - I'll call them now

after 2 flex plates and a complete rear differential...i will in fact sleep better knowing they will fix it - my dealer/service guys are great

Red C8 of Jax

Had same symptoms at 9-10K miles, dealer said it was a bad O-ring in the torque converter. New torque converter installed, now a pleasure to drive car. No more shuddering. OP if you do a search under" symptoms of a bad torque converter" you will find a lot of posts.

Rd16rr

...doing that now.....thanks !

Rd16rr

Found This:
https://www.corvetteforum.com/forums...r-failure.html

thanks

seCen

I had my flex plate replaced too and I know for a fact that there's a whining noise when I let go of the throttle and I can kind of hear it when I accerelate but the service people said that it's normal and not every vette is the same...not going to them anymore. I've had enough.

Told them about looking into the tsb about bad torque converter.....nope, their excuse was its normal.

Red C8 of Jax

Try to find a dealer who has replaced the A8 transmission or the A8 Torque converter. The first dealer I took my A8 to said nothing was wrong with my A8. Found a dealer who had replaced 3-4 Bad torque converters and took my car to them. Service writer took my car to the Corvette Tech and brought it back in 15 min and said my A8 had a bad o-ring in the torque converter and they would order the revised torque converter.

seCen

The only competent dealership is about a 45 minute drive for me. Was avoiding going out there because I didnt want to drive out there for nothing if they cannot find anything wrong. But other problems has arisen so this trip will definitely be worth it.