[dickh]

Just returned from the Texas Mile. Mods gave me 625 at the wheels and wanted 180 from that as stock ones were running 173-174. First run in Tour netted 176, but the 3-4 shift was terrible - simply laid down for nearly a second. Read another member had tried unhooking the battery, which I did. Next run with everything turned off, got a little sideways on the 1-2 and 2-3 shifts (my fault) and ran 175 with no shift problems noticed. Then ran it in Sport and had the same shift problem 3-4, and had slight crosswind for 172. Have taken it to the dealership and they said I have all the latest programming upgrades and the fluid is fine. No mods were made to the transmission as tuners don't have access to the programming yet. To further compound the problem, if I'm running at say 60 and nail it, the 3-4 shift works just fine. Repeatedly.
As this site has been remarkably good about advice, thought I would throw this out for help.
Thanks

[hawk02]

My gut reaction is your car experienced knock and the ECU pulled timing. Only way to know is to datalog. I assume at that power level your car has been tuned. Would also be helpful to know what mods have been done.

[17CamaroZL1]

Sounds like you hit the rev limiter on the 3-4 shift. I had that happen to me once at the strip. I thought something was going on with the engine while it was happening, but it took back off and had me scratching my head until I watched the PDR video afterward. That's where I saw the car hit the rev limiter due to a slow shift. Scrolling through all the gauges revealed the trans temp was the lowest it had ever been during a run, as it was only 150 degrees after making that pass. I immediately made a second pass and it shifted fine. Since that run, I've always made sure my trans temp is at least 150. Hasn't done that since. Even at full operating temp, the PDR videos show the 3-4 shift occur later than any other, so even at normal temps, I could see that possibly happening with a higher powered car that hasn't had the trans tuned. Did you happen to let the car sit and cool prior to the 3rd pass when it happened again? Just wondering if it was related to a cool trans like mine apparently was.

[dickh]

Thanks for the responses. You wait in line to run at the mile for sometime and I did not check the trans temp, which I will sure do next time. Car has a 15% pulley, Roto-Fab, Mamo, colder plugs and a great tune for 93. Also put in a can of Torco before the runs. Knock shouldn't be a problem but will check on that too. 180 is still the goal so now I have an excuse to go back after the checks.

[thompstl1]

Originally Posted by dickh

Just returned from the Texas Mile. Mods gave me 625 at the wheels and wanted 180 from that as stock ones were running 173-174. First run in Tour netted 176, but the 3-4 shift was terrible - simply laid down for nearly a second. Read another member had tried unhooking the battery, which I did. Next run with everything turned off, got a little sideways on the 1-2 and 2-3 shifts (my fault) and ran 175 with no shift problems noticed. Then ran it in Sport and had the same shift problem 3-4, and had slight crosswind for 172. Have taken it to the dealership and they said I have all the latest programming upgrades and the fluid is fine. No mods were made to the transmission as tuners don't have access to the programming yet. To further compound the problem, if I'm running at say 60 and nail it, the 3-4 shift works just fine. Repeatedly.
As this site has been remarkably good about advice, thought I would throw this out for help.
Thanks

Hi Dick,

I'm the member that had the same problem at the Mile. Looks like disconnecting the battery worked for both of us.

I took mine to the dealer also, and he said I had the latest transmission tune too and they had no idea what could have been wrong. I even showed them the car's video of the shift hanging up on 3-4. They were at a loss.

My car didn't have the problem prior to the Mile, and hasn't had it since. So hopefully we know how to correct the problem even if we don't know what induces it.

P.S. My problem at the Mile was during COLD weather and no way my temps were high. As a matter of fact, I was worried cold temperatures may have caused the problem so I remember letting the car idle a long time making sure it was warm.

The tuner that suggested disconnecting the battery told me the A10's sometimes "learned" bad behavior and disconnecting the battery deleted it.

Anyways, if you find out anything, please let us know!

[dickh]

Well, it worked the first time after I unhooked it, but I had all the controllers off. The next run in Sport it did it again. By the way, my understanding wife watched me unhook the battery on a locked car and close the trunk. Oops. She then, being smaller than me, crawled through the rear seat (at least I could open the door with a key) after a trip to the hotel bar, and pulled the glowing little handle to open the trunk as I couldn't get it to open with no power or a key. Still hearing about it today -"Nice going Mr. Racer mechanic."

[17CamaroZL1]

Originally Posted by dickh

Well, it worked the first time after I unhooked it, but I had all the controllers off. The next run in Sport it did it again. By the way, my understanding wife watched me unhook the battery on a locked car and close the trunk. Oops. She then, being smaller than me, crawled through the rear seat (at least I could open the door with a key) after a trip to the hotel bar, and pulled the glowing little handle to open the trunk as I couldn't get it to open with no power or a key. Still hearing about it today -"Nice going Mr. Racer mechanic."

[rjacobs]

I thought I read that 1-3 is on one gear set and 4-6 is on a second, and 7-10 on a third. I might not have the splits right though.

If thats the case, the 3-4 stumble/lag makes a LITTLE sense as its transitioning from one gear set to another... However, its always supposed to have 2 of the 3 gear sets spinning and ready to engage, thats why its so fast.


Im wondering why you were running in touring mode and not race, with touring suspension? That in theory gives you the best shift performance with the softest suspension to try to hook it up.

[dickh]

Originally Posted by rjacobs

I thought I read that 1-3 is on one gear set and 4-6 is on a second, and 7-10 on a third. I might not have the splits right though.

If thats the case, the 3-4 stumble/lag makes a LITTLE sense as its transitioning from one gear set to another... However, its always supposed to have 2 of the 3 gear sets spinning and ready to engage, thats why its so fast.


Im wondering why you were running in touring mode and not race, with touring suspension? That in theory gives you the best shift performance with the softest suspension to try to hook it up.

Just learning the car and experimenting for mile applications. Looks like I'm going back so your suggestion is appreciated and will give a try and report back on the next run. Thanks

[rjacobs]

There is a mile event first weekend of May in Blytheville, AR, that the group I run with here in Dallas is putting on. Will be a small event with lots of runs. They are estimating 15 runs a day if you want to as they are limiting the amount of cars that can show up.

[thompstl1]

Originally Posted by rjacobs

I thought I read that 1-3 is on one gear set and 4-6 is on a second, and 7-10 on a third. I might not have the splits right though.

If thats the case, the 3-4 stumble/lag makes a LITTLE sense as its transitioning from one gear set to another... However, its always supposed to have 2 of the 3 gear sets spinning and ready to engage, thats why its so fast.


Im wondering why you were running in touring mode and not race, with touring suspension? That in theory gives you the best shift performance with the softest suspension to try to hook it up.

I know when mine was shifting poorly at the Mile the engine would rev to about 5,700 rpms and it would "hang" there in 3rd gear (like the rev limiter was engaging). After about 2 seconds, it would shift to 4th. By then, you're not competitive with any similar cars.

I tried every mode and every combination I could come up with, and all produced a failed shift. There were two other ZL1's running at that time with no problems, and I tried duplicating their modes with no success.

After disconnecting the battery, my one final run (and the best of the weekend) the car shifted just fine.

I really have no confidence it will shift correctly next time I'm at the Mile, but we will see...

Really hoping someone comes up with a solution!

I tried to talk Parkland Chevrolet (in Tomball) to simply reflashing the transmission computer, but they wouldn't do it. Hell, they wouldn't even try and duplicate the problem as they said they couldn't drive the car over the speed limit when checking it out. Even though they watched the video of the transmission stumbling, it didn't seem to be enough to motivate them to try any kind of fix at all. Frustrating to say the least.

[thompstl1]

I went back and carefully reviewed all of my PDR videos of the Mile run. I did find something that could be contributing to the bad shift;

It was a cool day (40's) and the runway in Victoria is really slick. In every instance I was fighting for traction in 2nd gear, was never able to completely give it full throttle and when shifting to 3rd the car would actually spin then too. It seemed as though the transmission/computer we getting a bit "confused" with all the traction problems for some reason. On the one shift where I took off pretty slowly (which happened to be after I disconnected the battery) I was not spinning in 2nd or 3rd (fast takeoff has limited benefit in the Mile when top speed is the only measure of success) and the transmission shifted flawlessly.

I'm wondering if the traction problems (much worse at the Mile than on a road here at home) could have somehow caused the issue?

I noted the OP was having significant traction problems too.

Anyway, a thought to keep in mind...

[dickh]

Originally Posted by thompstl1

I went back and carefully reviewed all of my PDR videos of the Mile run. I did find something that could be contributing to the bad shift;

It was a cool day (40's) and the runway in Victoria is really slick. In every instance I was fighting for traction in 2nd gear, was never able to completely give it full throttle and when shifting to 3rd the car would actually spin then too. It seemed as though the transmission/computer we getting a bit "confused" with all the traction problems for some reason. On the one shift where I took off pretty slowly (which happened to be after I disconnected the battery) I was not spinning in 2nd or 3rd (fast takeoff has limited benefit in the Mile when top speed is the only measure of success) and the transmission shifted flawlessly.

I'm wondering if the traction problems (much worse at the Mile than on a road here at home) could have somehow caused the issue?

I noted the OP was having significant traction problems too.

Anyway, a thought to keep in mind...

We were running in about 60 degrees and the runway has improved slightly traction wise according to the folks who were there in Oct. The only time I got slightly sideways was with all the controls off, but again, that's on me. The 1-2 and 2-3 shifts were solid, but I was following the mile method of slow initial takeoff, which I have used for the last four times I've run. Real reason for that is several folks took me aside on my first visit and explained why. As they were all running over 200, I thanked them and followed the suggestions. Now I'm trying my wife's patience considering Arkansas...

[Jason@JacFab]

Not exactly on the same field, but even in my A8 2.0 car, the 3-4 seems to be the worst/slowest shifting. A10 tuning not available yet? A8 tuning is there, but extremely limited in comparison to the old A6 stuff. I found that part of MY 3-4 shift issues were torque converter related. In the stock tune, the converter locks immediately after the 1-2 shift, and if you try to make the shift quicker on the 3-4 with the converter locked, bad things happen. The fix was to keep the converter unlocked until after the 3-4 shift, and it fixed all the issues I was having with the 3-4 shift.

Not that this helps you right now, but at some point when a10 tuning becomes available to you, it might be worth looking at.