usmcpony

I've searched the forum and can't find anyone with the same issues so I'm throwing in the towel and making this thread. I have a 2013 grand sport with 780rwhp. It has a ecs 1500 supercharger, cam, exhaust and built transmission. I just bought the car used with 2000 miles. My issue is when my trans temperature get to 190 degrees it won't shift in S mode when I want it to. I have to be going 20 mph to shift into 2nd, 30 mph to shift into 3rd, 40 to shift into 4th, 50 to shift into 5th and won't shift into 6th at all. If I'm on the highway going 70+ mph it will automatically down shift into 5th and will not let me up shift into 6th. It does the same thing in automatic. I thought it could be a heat issue but it had done it twice when trans temperatures was only at 130 degrees. But more common when it reaches 190 or above. It got to 230 degrees once and I had to pull over and let it cool. Thanks for your help

realcanuk

Definitely sounds like a mechanical issue within the trans. Check ***** sticking or solenoids ??? I don't know enough about them mechanically to help but am very interested to hear what causes this.
You say its a built transmission. I would speak to whoever built it for advice.

EOD_Tech Infidel

have you checked the transmission tune?

usmcpony

It doesn't do it until the transmission gets warmed up. Its done it twice with low temperatures. if it was mechanical wouldn't it do it all the time? I called the shop and they said they don't know what could be causing it.

usmcpony

I'm not sure how to do that. This is my first corvette and my first automatic.

theVcar

What shop did you call?

usmcpony

Ecs. They built it and tuned it.

RamAir972003

That's odd if they built it and tuned it why would they say that.. Doesn't sound right to me...

realcanuk

Really doesn't sound like something ECS would say.

The reason I say it sounds mechanical is because I am assuming it was fine and then this issue started happening. Tunes don't change by themselves.

theVcar

I disagree, it's VERY ODD. They stand behind their work

Pitufina

Could be the tranny tune. I know that some tuners are more into the automatics than others. So my first thought would be if the ECS tuner is good with auto tuning or not. I would call them and try to talk to the tuner.

usmcpony

They've helped me out on the phone allot. It's not that They aren't standing behind their work they said they haven't had this particular issue before. I took it to the dealership I bought it from and they couldn't find a code or heard of this problem.

realcanuk

Could be a tough one to figure out. May be worth giving century a call and see I'd they've seen that problem before.

usmcpony

I'm assuming you're talking about Century automotive? I've never dealt with them before but this would be a good start. I'll definitely give them a call.

realcanuk

Yes. or contact Christopher (subfloor on this forum). He is a the 6L80 guy here and works closely with them.

usmcpony

I'll call the shop and see what they say. Hopefully someone else has had and fixed this issue. That would help out allot. I appreciate everyone's help.

C7/Z06 Man

Just to see if it makes a difference I would change the fluid/filter with "OEM", with a bottle of that lucas shift stuff. Give it some time to do its thing. If you don't want to change the fluid than just add the lucas shift stuff, with what is going on it might be worth a try. I have had stuff like that happen to me in the past; delayed shifting, hard shifting, etc. and sometimes this kind of stuff has helped. You just may have some stuff that starts to stick when things heat up/expand or from "crud buildup" and you do have a second trans cooler in series with the OEM I'm sure.

PS: I have ran my GS "Hard" alot (every weekend) with many burnouts against the brakes up to a while ago (line lock) which is even harder on the trans, well I started to get a very noticeable down shift when coming to a stop. A OEM fluid/filter change fixed that but it took a week or two of driving the car around regular to work it completely out, however I did notice the trans was smoother right after the fluid change and I do have a second trans cooler in series.

That shift stuff has worked well for me in the past, made the car shift as it should and that was right after a fresh rebuild with fresh fluids; worth a try in my book before a big expense and "yes" the experts may disagree. Your problem is much bigger than mine, so that is why I'm suggesting the shift stuff too.

CI GS

Is this car the white anniversary car that ECS has a video of on their site that went 9.78? If so, I would think they would be very interested in fixing a "poster child".
So, it came with this problem? Or did this just start all of a sudden? I would do an ATF and filter change as suggested above first. I would stick to using the stock GM recommended Dextron VI fluid, as that is reportedly formulated specifically for the newer non-steel clutch packs like in the 6l80E, unless ECS tells you otherwise (as they probably changed the clutches if they built the trans).
BTW: Have you already eliminated the simple stuff like check the fluid level?
On the one hand, it sounds mechanical but it could be a problem with the tune. In any event, I would see if I could get the car transported to ECS and get them to sort it out. One thing is for sure, at that power level, you shouldn't drive it around too much and definitely don't hammer it before you get this sorted, or you might end up buying a new transmission.
Good luck with getting it sorted and please let us know how it goes.

timd38

Red Line Ester based lube will take heat much better than conventional and other synthetics.It also is more stable as it heats up.

It worth a try.

Vis @ 100°C, cSt 7.5
Vis @ 40°C, cSt 34
Viscosity Index 198
Pour Point, °C -60
Pour Point, °F -76
Flash Point, °C 225
Flash Point, °F 437

realcanuk

Please update this thread when you solve this issue. I am running 780 through a 6L80 also and like to keep on top of these things as I know issues are coming soon..