Auto transmission slipping when cold
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7th Gear
Joined: Jan 2018
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Auto transmission slipping when cold
2015 C7 stingray Z51 automatic when in economy or sport or any mode I go down hill on my corner and I feel a like lockup then slip and then it is ok the rest of trip till I start out cold the next day
Thread Starter
7th Gear
Joined: Jan 2018
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[QUOTE=eweinere;1596296996]2015 C7 stingray Z51 automatic when in economy or sport or any mode I go down hill on my corner and I feel a like lockup then slip and then it is ok the rest of trip till I start out cold the next day and still slips. I went to Simson Chevrolet and they said that this issue is NORMAL but recommended per their transmission tech Marco I can get an upgraded software for the transmission so I went back left the car all day and next day still slips , I called my service advisor Keiki and he said the slip is NORMAL again and that I needed to put more miles on car to fix . I have 3600 miles on it now ???
Tech Contributor
Joined: Oct 1999
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From: Charlotte, NC (formerly Endicott, NY)
Lock up would be when the Torque Converter Clutch activates. Slipping would be when the TCC deactivates leaving you running with just the torque converter which like all torque converters does slip. Since this is happening when the car is cold it sounds like maybe the TCC is activating and locking up when it shouldn't. As far as I know they don't want it to lock up when the engine isn't warmed up. Did they leave the car outside over night to let it get good and cold before trying to diagnose the issue? If the car is inside and warm before they start working on it they may never see the problem.
Bill
Bill
Race Director
Joined: Apr 2003
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From: moraga ca
It's hard to determine if a transmission is slipping when going downhill. Are you on or off the gas when this happens. What happens when you start going uphill in the morning? Possibly you are feeling off throttle upshifts which can feel uneven or jerky.
Safety Car
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I agree and the initial 1 to 2 upshift can be harsh, particularly with the earlier iterations of the 8L90. As an experiment next time before leaving your house while stopped in the driveway put the transmission in manual mode and paddle shift up to two then place the transmission back in auto mode and start your drive. If it is the initial 1 to 2 upshift causing this behavior it should disappear for that drive cycle.
Thread Starter
7th Gear
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I am not on the gas when going downhill and I never go uphill on cold start thanks a lot Eugene
Safety Car
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The downhill is where the first 1 to 2 upshift is probably going to occur unless you build up enough speed before reaching that point. I would on rare occasion get the initial 1 to 2 rough shift shortly after I pulled out of my driveway and before I got to a more major road. I have started manually shifting into and out of 2nd before I start down the drive and that has ended that issue. Give it a try next time you head out.
