11-17-2019, 02:24 PM | #1 |
Drives: 2017 1SS Blue Join Date: Mar 2010
Location: Saint Peters, MO USA
Posts: 2,063
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Vibration/Hesitation When Torque From Engine Gently Applied
I have a 2017 1SS with 24,000 miles, automatic transmission and I'm encountering a strange vibration/hesitation when torque from engine is gently applied going up a hill on cruise control or off cruise. Most noticed when applying small increases in torque such as when car encounters an incline or going up a steeper hill. Coming down hills even at high speeds (80 MPH+) reveals no vibration or hesitation at all. Going up the hill (even on a 60 MPH crawl) feels like 2 seconds of smoothness followed by 2-3 seconds of vibration (similar to hitting the edge of an interstate when it shakes to wake you up). I believe it's an engine or transmission thing but no "check engine" lights at all. Wheels are all balanced and alignment is spot on so uncertain of what is going on. If you have experienced this please advise.
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11-17-2019, 02:27 PM | #2 |
2019 ZL1 1LE MY GOON
Drives: 1980 Z28 Big Red. Join Date: Dec 2018
Location: Stoney Creek
Posts: 2,061
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I’m thinking torque converter issue when it’s applying or releasing. These auto transmissions are known for torque converter issues. May wanna read up on the issues in the transmission section on this site.
Now I can’t say I have felt this in a sixth Gen Camaro but by your description and the fact I’ve been a licensed auto tech for 25 years your description sounds like a torque converter issue. Only other thing I could think is a minor misfire the ecm can’t detect yet and therefore the check engine light isn’t on. I’d put my money on the torque converter. |
11-17-2019, 02:31 PM | #3 | |
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11-17-2019, 03:58 PM | #4 |
Drives: 2017 1SS Hyper Blue Join Date: Apr 2017
Location: Wisconsin
Posts: 478
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Yep, A8 shudder. I’ve had it, you are describing it spot on. Watch your tach closely as well, you might even see a little rpm fluctuation that coincides with the shudder.
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11-17-2019, 04:09 PM | #5 |
Drives: 2018 Camaro 2SS A8 Join Date: Jul 2017
Location: East Tennessee
Posts: 12,025
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OP, there is a service bulletin, number 18-NA-355, to address this problem. Visit your dealer ASAP and get it applied. The dealer should not ask any questions but perform this 1.5 to 2-hour procedure upon request.
If it does not fix the condition, you need to go back and get the torque converter replaced. Both the flush and the new torque converter are covered by the powertrain warranty, so you should be good either way. The underlying story in a nutshell is that this is a known hardware+software problem with the A8 transmission from the beginning, it affects every GM car and truck that has this unit, and GM attempted to fix it in various ways with different fluids and revised torque converters earlier. The latest transmission fluid flush specified by 18-NA-355 apparently solves the problem for the vast majority of users. For those that went to the dealer too late and lived too long with the condition, the recurring shudder may have damaged the torque converter, so that may need to be replaced as well.
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2018 Camaro 2SS — G7E MX0 NPP F55 IO6
735 rwhp | 665 rwtq Magnuson TVS 2300 80mm pulley | Kooks 1 7/8" LT headers | JRE smooth idle terminator cam | LT4 FS & injectors | TSP forged pistons & rods JMS PowerMAX | DSX flex fuel kit | Roto-Fab CAI | Soler 95mm LT5 TB | 1LE wheels | 1LE brakes | BMR rear cradle lockout | JRE custom tune 1100 - 1/30/18 | 2000 - 1/31/18 3000 - 2/06/18 TPW 2/26/18 3400 - 2/19/18 | 3800 - 2/26/18 4300 - 2/27/18 | 4B00 - 3/01/18 4200 - 3/05/18 | 4800 - 3/14/18 5000 - 3/16/18 | 6000 - 3/19/18 |
11-17-2019, 04:33 PM | #6 | |
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11-17-2019, 05:48 PM | #7 |
Drives: 2017 1SS Blue Join Date: Mar 2010
Location: Saint Peters, MO USA
Posts: 2,063
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Thanks to everyone who diagnosed my car’s condition. SB 18-NA-355 torque converter. Should I drive it in manual mode until I get it in?
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11-17-2019, 06:00 PM | #8 |
Biggest thing is trying not to get the car to go into V4-V8 vice versa. One thing that I’ve heard is try to not drive in tour mode but rather sport or track mode. To answer your question, to avoid any further damage I would drive in manual mode.
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11-17-2019, 08:33 PM | #9 |
Drives: 50th Anni.. coming home 11/01 Join Date: Jul 2014
Location: Toronto. Ontario
Posts: 1,639
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yep.
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Built Sept 16/2016 - #2681 of 5955. She came home with me 11/01/16. 50th Anni, 2SS, A8, NPP, NGM Rock Guards, Footwell Lighting, Black Bow Ties, Street Warrior Rotors and Pads, Ceramic Pro, 3M PPF, Oracle Ghosted Side Markers, Kooks 2" headers w/hi flow cats. GPI Stage 1 Cam installed at 305,000 kms. |
11-18-2019, 02:06 AM | #10 |
Drives: 2017 2SS M6 Join Date: Jun 2013
Location: WNY
Posts: 7,069
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get it right in its free and set an appointment for a loaner.
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real ZL1 wheels and brakes, 285/305 Michelin Pilot Super Sports, Pray ported Intake manifold, Soler Throttle Body, Rotofab intake, EFI Tuning Flex fuel kit, full American Racing Headers Exhaust, 1 7/8" w/ cats H pipe and mufflers. Full 1LE suspension, with BMR adjustable sway bars and links, GM aluminum cradle bushings, Hurst shifter with lighter reverse spring, TWM shifter knob, Tick level 1 transmission. I should have bought a ZL1
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