trans not shifting
trans not shifting Finally got to the track tonight. Fairly humid (fog was rolling in). Wish I had one of those weather stations to see what conditions were for sure. Last I checked it was at 81% humidity (according to the weather channel).
Anyway, I ran her down the track. First run, bouncing off the rev limiter on the 2-3 shift about 6 to 8 times before hitting third gear, I run a 13.20 at 103.
I'm pretty happy at that point... thinking I'll pull the laptop out, adjust shift points and break the 12s by the end of the night.
Well, I had that laptop out after EVERY run tonight and couldn't get that shift to go like it should. The car gets to 5500 rpm, then it acts like it goes in neutral because the tach jumps from 5500 to 6500 and starts bouncing the rev limiter. Usually about 5 to 6 times before it would go into third. No matter what I did in the ecm, this happened on EVERY run.
Nice thing was I had some dead consistent runs. I tihnk I had 3 of them at 13.16x at 103.95x Literally almost identical to the thousandth of a second.
Anyway, by the end of the night, I pulled the K&N (because it was looking pretty grubby) and turned a 13.069 at 104.43 and backed it up with a 13.053 at 104.37 and it's STILL bouncing off the rev limiter.
Any help? I have the 2-3 shift down to 69mph and rpm at 6000. Rev limiter is 6500 and it still hits it when the speedo is showing 80+ and the tach is redlined.
This all started when I went from the 2.73 gears and stock converter to 3.42 gears and SY3500 converter.
Gotta be something I am missing.
Anyway, I ran her down the track. First run, bouncing off the rev limiter on the 2-3 shift about 6 to 8 times before hitting third gear, I run a 13.20 at 103.
I'm pretty happy at that point... thinking I'll pull the laptop out, adjust shift points and break the 12s by the end of the night.
Well, I had that laptop out after EVERY run tonight and couldn't get that shift to go like it should. The car gets to 5500 rpm, then it acts like it goes in neutral because the tach jumps from 5500 to 6500 and starts bouncing the rev limiter. Usually about 5 to 6 times before it would go into third. No matter what I did in the ecm, this happened on EVERY run.
Nice thing was I had some dead consistent runs. I tihnk I had 3 of them at 13.16x at 103.95x Literally almost identical to the thousandth of a second.
Anyway, by the end of the night, I pulled the K&N (because it was looking pretty grubby) and turned a 13.069 at 104.43 and backed it up with a 13.053 at 104.37 and it's STILL bouncing off the rev limiter.
Any help? I have the 2-3 shift down to 69mph and rpm at 6000. Rev limiter is 6500 and it still hits it when the speedo is showing 80+ and the tach is redlined.
This all started when I went from the 2.73 gears and stock converter to 3.42 gears and SY3500 converter.
Gotta be something I am missing.
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
Well, I had that laptop out after EVERY run tonight and couldn't get that shift to go like it should. The car gets to 5500 rpm, then it acts like it goes in neutral because the tach jumps from 5500 to 6500 and starts bouncing the rev limiter. Usually about 5 to 6 times before it would go into third. No matter what I did in the ecm, this happened on EVERY run.
However... let's rule out tuning as an issue first... what software do you use to modify your PCM? also would be helpful if you list your mods (all of them, as well as the year of your car)
1999 Camaro Z28 convertible. 79k miles
A4 trans with SY3500 converter
long tube headers with ORY and hooker aerochamber muffler
K&N filter in a whisper lid with free ram air
coolant bypass
!EGR and !AIR
3.42 gears
ET streets
and I use LS1 edit to tune.
A4 trans with SY3500 converter
long tube headers with ORY and hooker aerochamber muffler
K&N filter in a whisper lid with free ram air
coolant bypass
!EGR and !AIR
3.42 gears
ET streets
and I use LS1 edit to tune.
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
hmmm... definetly sounds like the transmission is slipping then 
setting the 2-3 shift to 69mph for all the WOT tables, and setting the shift RPM to 6000RPM should cause the trans to shift just after 6000 (well PCM will command shift then, there's some delay so actualy shift would prolly be 6150) but still well below your 6500 rev limiter....
Sounds like the clutches just can't hold and are slipping... check the trans fluid level, and smell the trans fluid to see if it smells burnt at all... but may be time to look into a rebuild
One thing possibly PCM related... if the converter is slipping bad... 20% loss through converter, at 6500RPM you'd be right around 70mph ... if the converter is slipping normally (~10% loss) you'd be at 70 around 5600RPM ... you could try lowering the MPH to like 50 .. but keep the RPM at 6000 (both conditions must be met for a shift... so if you set shift speed to 50, and RPM to 6000, it'll shift if RPM >=6000 and MPH >=50) and see if it still does it...
if it seems to shift ok then you're loosing ALOT through your converter (my last converter was slipping 20% on me through my 382... but it was a vig... known for less efficiency) and it may be just the torque converter... but w/your mileage, slicks and feeling like it's in neutral before it finally shifts (bounching several times too) sounds like the trans is toast
setting the 2-3 shift to 69mph for all the WOT tables, and setting the shift RPM to 6000RPM should cause the trans to shift just after 6000 (well PCM will command shift then, there's some delay so actualy shift would prolly be 6150) but still well below your 6500 rev limiter....
Sounds like the clutches just can't hold and are slipping... check the trans fluid level, and smell the trans fluid to see if it smells burnt at all... but may be time to look into a rebuild
One thing possibly PCM related... if the converter is slipping bad... 20% loss through converter, at 6500RPM you'd be right around 70mph ... if the converter is slipping normally (~10% loss) you'd be at 70 around 5600RPM ... you could try lowering the MPH to like 50 .. but keep the RPM at 6000 (both conditions must be met for a shift... so if you set shift speed to 50, and RPM to 6000, it'll shift if RPM >=6000 and MPH >=50) and see if it still does it...
if it seems to shift ok then you're loosing ALOT through your converter (my last converter was slipping 20% on me through my 382... but it was a vig... known for less efficiency) and it may be just the torque converter... but w/your mileage, slicks and feeling like it's in neutral before it finally shifts (bounching several times too) sounds like the trans is toast
Last edited by horist; Sep 4, 2004 at 12:07 AM.
