Trans hanging up 3-4 shift.. only at the track.

[syP]

Last weekend i went to the track bone stock to run my car.


to my surprise i hit a 13.48 @102mph.


BUT, every single time, im about to cross the line at the 3-4 shift, and it literally hangs up there at redline (almost like its in neutral), then it shifts into 4th about 1.5 seconds later

I added headers/xpipe and went back to the track today in hopes for a 12.9999 pass. I could only muster a 13.12, 13.14, 13.15 (consistant huh? :) )

I tried DRIVE, SPORT, and SPORT then shifting manually into 4th, and SPORT manually holding 3rd gear, but ended up hitting redline.

1.5 seconds is a VERY VERY long time to shift in a race. I know these stocks TCM tunes are garbage, but on the street, i give a lot of people rides because they wanna see how the car is. it ALWAYS snaps into 4th gear on the street. What gives? :spank:

[Tate]

I've had the same issue for the last 5 months. This is with the VMS tune, but haven't talked to Kirk yet to see what he could do. I'm sure it is something that can be tuned out.
Tate

[GRRRR8]

Last weekend i went to the track bone stock to run my car.


to my surprise i hit a 13.48 @102mph.


BUT, every single time, im about to cross the line at the 3-4 shift, and it literally hangs up there at redline (almost like its in neutral), then it shifts into 4th about 1.5 seconds later

I added headers/xpipe and went back to the track today in hopes for a 12.9999 pass. I could only muster a 13.12, 13.14, 13.15 (consistant huh? :) )

I tried DRIVE, SPORT, and SPORT then shifting manually into 4th, and SPORT manually holding 3rd gear, but ended up hitting redline.

1.5 seconds is a VERY VERY long time to shift in a race. I know these stocks TCM tunes are garbage, but on the street, i give a lot of people rides because they wanna see how the car is. it ALWAYS snaps into 4th gear on the street. What gives? :spank:

You need a tune to up your shift point as you should still be in 3rd gear when going through the traps. Thats why you are not in the 12s.

[syP]

Thats what i thought, but i was reading a lot of posts on the other board, and people with the VMS tune were seeing the same thing as me.

ya, we were really hoping for a 12 second pass. God this irritates me. On the way home today... crisp clean 3-4 shift.

my TBSS friend said something about the pcm/tcm learns how you drive... so if you take a long trip... ie.. track... it will learn to shift slow and mushy because of the all the highway driving. He suggessted that i unplug the battery for 30 minutes before i take her down the track.

[syP]

I think i found out "why" it does this..


EVERYsingle time in the staging lane, i would shut my car off to cool her down... then when our lane was about to go, id start her back up. EVERY time i did that, the trans would shift weird from 3-4.


I went to the track the other night and it did the same thing. There was no one in line so i hotlapped. Did not turn the car off. Went up to the line, burnout, then went down the track. It shifted flawlessly 3-4. I left the car running for the next 3 runs. It shifted flawlessly again.


After that i shut it down, started it up, and then went down the track. It hung up HARD 3-4 shift.

[johnh]

I have the same thing, don't know if its temp related or what.

I am trying to tune it out now, but its hard to test WOT 3-4 shift if you're not a the track...I've adjusted the intertia torque profile to look more like 2-3 shift.


You need a tune to up your shift point as you should still be in 3rd gear when going through the traps.

What do you recommend for shift points? Mine still doesn't shift the same way twice...it seems to vary by several hundred rpms either way.

[syP]

thank god i got a nice road by me to test it...


but yea.. keep it in the back of your minds if you have this problem.. and just try once to hotlap the shit out of the car... DO NOT turn it off.

I dont think it necessarily has to do with temperature... but maybe "the first WOT after the car is turned on"??

[Tate]

Kirk had said the same thing a while ago. Leave the car running and hit the line again. But when your trying to get good times it's a bit hard to hot lap a car and get better times, and now it's getting warm/hot weather to race in.
Tate

[cobrakid]

My G8 shifts a little weird for the first shifts after start up then never does it again?????

Mine is usually 1st to 2nd.

[PerfectD3]

Just tested this out at lunch (I just finished tweaking the tranny with hpt) and I got the same results. First WOT was nasty, ate, went back out and she just hung there between the shifts.

[syP]

i wonder if this can be tuned out

[breakinparts]

i wonder if this can be tuned out

Well obviously if this is the case with hot lapping, yes it could. Something in the tune is not allowing it to shift right after start up. I notice this even driving to work not getting on it.

[breakinparts]

I let the car shift at the track and would hang up every time on the 3-4 shift. I never hot lapped it. I only made a few passes, but with the shorter 275-40-17 tires I do not feel comforble holding it down in 3rd trapping almost 110 with the stock timing tensioner.

It would be nice if there was some way to turn off these learning variables in our ecu's. I'm pretty sure this is why our cars can feel flat sometimes, and after unhooking the battery for a few minutes it will feel like it picked up in SOTP

[wreckwriter]

Cooling down between runs should not be cooling your car far enough down that you get cold shift issues. If it is you're cooling too much. Car needs to be at operating temp.

Compare your normal and sport shift profiles to the "hot" and "hot engine" profiles, see where the shift points are set.

[breakinparts]

I'll talk to Kirk and see what he has to say. He just ironed out an engine tune issue and now hopefully he can iron this issue out too.

[wreckwriter]

I'm sure he can :)

[GTeve]

bump! I've had the same 3-4 shift hold up at the track and want to know how to fix it.

[fiveoh]

bump! I've had the same 3-4 shift hold up at the track and want to know how to fix it.

I had this as well my last trip to the track. I sent vector an email about it and they redid my tune and said it should fix it. I havent made it out to the track since then so I'm not sure if its fixed or not but maybe you should contact livernois about it.

[Kirk@VectorMotorsports]

I believe I have the fix for this.

Anyone with the PowerFlash going to the track soon that can test it?

If so shoot me an email to kirk@vectormotorsports.com and I will send you an updated file.

[fiveoh]

I'm going on Saturday as long as it doesnt rain. I'll let you know. Sent you an email saying the same thing too.

[G8-4-Speed]

Yep, same issue, always holds the 3-4 shift from a start-up :hang:plus there is a little extra rpms on the other shifts. Always run my fastest time from a hot-lap....Still looking for the cure.....

[Patrick G]

Weird, I always finish in 4th gear and it never hangs up on me. I always keep my hood open and cool off the car with the motor off between runs. I start it up right before the run. I never even knew this was an issue. Maybe I should put my tranny tune back to stock and see if it does it then.

[-Ray-]

Mine hangs as well. Sometimes it'll hit the rev limiter and not shift at all. Well, that only happened a couple times, since I'm manually shifting the 3-4.

[GeorgeInNePa]

I had this problem yesterday at Cecil. It was hanging up every shift. Devilish34 tipped me that it was happening to him when he did his burnout in M, then switching to D for the run. He said it stopped doing it when he started doing the burnout in D and then using D for the run.

Sure enough, when I did the next run, D-burnout and D run, it shifted great!

I let it shift into 4th also...

[edmanet]

I had this problem yesterday at Cecil. It was hanging up every shift. Devilish34 tipped me that it was happening to him when he did his burnout in M, then switching to D for the run. He said it stopped doing it when he started doing the burnout in D and then using D for the run.

Sure enough, when I did the next run, D-burnout and D run, it shifted great!

I let it shift into 4th also...

Yeah we do share our secrets....LOL

[WARLOCK]

im bumping this thread back up because my car is doing it too. I have tried making all my 3-4 shift parameters match the 2-3 ones in the tcm and it still does it. did anyone find a fix?

[Patrick G]

Make sure your TCC is not engaging at WOT in 4rd gear. The torque converter clutch is set to engage at 95mph at WOT from the factory. This can mess up your 3-4 shift. Set your TCC to not engage in 4th gear above 85% TPS or at WOT (all tables). This may help.

[WARLOCK]

COOL thanks for the info. will try that as well.

[youngrushhour]

Has anyone found a 100% fix for this yet? Is running the car in D a real fix and all? The TCC fix work for anyone? This issue has been pissing me off for some time now.

[blackbirdws6]

I had this same issue until I finally bit the bullet and had Jeremy @ Fasterproms retune the car. 3-4 shift issue solved lol.

I haven't been back to the track yet but was able to get a few WOT runs on "closed courses" to try it :)

[bluegoat06]

Bumped to see if somebody have found the cause for this ? i did open a thread at HPT forums to see if there was some sort of diagnostic test being run when the engine is started after a cool down period. this 3-4 WOT hanging issue doesn't happen on the street, only at the track, if the car is hot lapped, she would shift as it should every time.

[Dagoon]

Same issue here.

[1ChargedG8]

bluegoat, this happened to me at the track once, hit the rev-limiter then car went nose down, but still was my best 11.32. I looked at the post in the hptuners forum, made few changes to the tune per you guys directions. I will experiment this weekend at the track. If you want me to log something let me know.

Alex

[bluegoat06]

Thanks Alex,
I created a new thread in the tuning section here http://forum.grrrr8.net/showthread.php?t=22650&p=334933#post334933

to follow up with the issue since it's not directly related to a trans problem, our trans are shifting as they should on the street, but something is happening after the first time the engine has started after a cool down and a WOT is made inmediatly after that. funny i can let the engine sit at idle for 30 min like it happened the last time i went to the track (staging lanes were just insane), and the stupid trans didn't shift as it should. i had to start the engine several times, and i couldn't let the trans shift into 4th at part throttle, so i knew my 3-4 was going to hang since it was the first run :(

I'm going to the track Feb 8 to test the changes i did to the inertia thing for the 3-4. i'm sure it won't fix it, but i guess i'll keep tyring :)

[gtp6515]

I had this same issue at the track recently. Did anyone ever find a resolution? I have a VMS tune as well, and thought my car was quite slow at the track due to this issue. Don't seem to get responses back too quickly from VMS.

[TonyKarter]

Same here. I rec'd a retune from VMS, second and third shifted harder, but same slow 3-4 shift.