Duramax Diesels Forum Truck of the Week
  #1  
Old 10-25-2009, 12:39 PM
coker6303's Avatar
coker6303 coker6303 is offline
Keep Calm and Chive On!!
 
Join Date: Aug 2009
Location: Houston, TX
Truck: 08 2500 CCSB 4x4
Engine: LMM
Transmission: Automatic
Posts: 2,284

Default strange 1st-2nd shift

I've been running Rob's 110hp tune on my LMM. Changed from a 70-80hp tune to Robs 110 and did the relearn. light and medium throttle shifts are spot on. Clicks through the gears perfectly. The weird part is at wide open throttle. If you roll along about 5mph and hit WOT the truck will go to shift into second and shut down. Feels like it makes the shift but drops all power, let off and get on it again and it takes off as if nothing happened. No codes. pulls great through 2nd, feels strange in 3rd (feels like you loose some accelleration and may be revving a little high) and then hits 4th perfectly and pulls hard again. Can't tell you about 5th and 6th, I don't pound it shifting into those gears. The TCM has not been changed, all stock shift points.

The only current mod to the tranny is the transgo jr kit. What do I need to be looking at in the ECM or TCM to get these shifts a little better? Any advice is appreciated.

Russ
__________________
Russ

2015 Denali LML CC/SB - staying stock!!
2008 reg cab 2wd LMM - at Top Notch Garage getting some loving!! Shooting for low 11's to high 10's
2008 LMM CC/SB 4x4 - SOLD
S364.5FMW / batmo S480 twins 40% overs dual CP3
11.85 @ 113mph

Thank you to JoshH, emiller3, and blksmokelb7
Reply With Quote
  #2  
Old 10-25-2009, 01:14 PM
Bako_Dmax's Avatar
Bako_Dmax Bako_Dmax is offline
GTO Slayer
 
Join Date: Apr 2008
Location: Bako
Truck: 2006 Chevy Dmax
Engine: 6.6 Dmax
Transmission: Automatic
Posts: 798
Default

I think your experiencing the truck defueling between shifts, which is saving your trans from slipping.
__________________
2006 Chevy LBZ
MBRP exhaust, Shimmed FPRV, Blocked EGR
Homemade Lift Pump W/ Bypass
Homemade Pitman & Idler Braces
Tierod Sleeves
EFI Live
Built trans w/ triple disc

Homemade Twins S475 w/ 38mm gate
Reply With Quote
  #3  
Old 10-25-2009, 01:17 PM
Mike L.'s Avatar
Mike L. Mike L. is offline
Got Sheep?
 
Join Date: Aug 2006
Location: Disneyland, CA
Truck: 2011 Chev CC SB 4X4
Engine: 6.6
Transmission: Automatic
Posts: 10,895
Default

Quote:
Originally Posted by Bako_Dmax View Post
I think your experiencing the truck defueling between shifts, which is saving your trans from slipping.
I totaly agree. Problem is; it still does a lot of damage to C3's even with the engine shut down. Need more trans.
__________________
Shop 714 870 7300
Cell 310 918 9678

Tuned by Idaho Rob.
Reply With Quote
  #4  
Old 10-25-2009, 01:55 PM
coker6303's Avatar
coker6303 coker6303 is offline
Keep Calm and Chive On!!
 
Join Date: Aug 2009
Location: Houston, TX
Truck: 08 2500 CCSB 4x4
Engine: LMM
Transmission: Automatic
Posts: 2,284

Default

Quote:
Originally Posted by Mike L. View Post
I totaly agree. Problem is; it still does a lot of damage to C3's even with the engine shut down. Need more trans.
one of these days Mike!! LOL

When it shuts down shifting from 1st to 2nd, I have yet to keep my foot on the floor. I let out and then get back in it. Guess I need to stay in it just to make sure it is the defuel....or we'll be building a tranny sooner than expected!!
__________________
Russ

2015 Denali LML CC/SB - staying stock!!
2008 reg cab 2wd LMM - at Top Notch Garage getting some loving!! Shooting for low 11's to high 10's
2008 LMM CC/SB 4x4 - SOLD
S364.5FMW / batmo S480 twins 40% overs dual CP3
11.85 @ 113mph

Thank you to JoshH, emiller3, and blksmokelb7
Reply With Quote
  #5  
Old 10-25-2009, 02:17 PM
The Neens's Avatar
The Neens The Neens is offline
BFD
 
Join Date: Aug 2006
Location: Valencia, Ca.
Truck: 2007 4WD CC/SB
Engine: LBZ
Transmission: Automatic
Posts: 5,181

Default

Quote:
Originally Posted by coker6303 View Post
one of these days Mike!! LOL

When it shuts down shifting from 1st to 2nd, I have yet to keep my foot on the floor. I let out and then get back in it. Guess I need to stay in it just to make sure it is the defuel....or we'll be building a tranny sooner than expected!!:D
I totally agree
__________________
2007 GMC 4WD CC/SB...McRat EFI Live, Trans, Trans Cooler and C3 Clutch Oiling Mod by Mike L., SD sleeves, SoCal Diesel

2002 Chevy 2WD CC Dually...McRat EFI Live, Trans, Trans Cooler and C3 Clutch Oiling Mod by Mike L., SoCal Diesel



Next Taps party on ??-??-??

The sooner you fall behind, the more time you'll have to catch up...

Team Arrogance Founding Member

The Gerbil Clubs founding Member#1
"Gerbil Trainer for the Stars"
Reply With Quote
  #6  
Old 10-25-2009, 03:57 PM
dwax's Avatar
dwax dwax is offline
Hotrodder
 
Join Date: Jul 2009
Truck: ccsb
Engine: LBZ
Transmission: Automatic
Posts: 185

Default

mine did the same thing (exactly) the first time i tune it with efi. turns out my old ppe was still hung in my computer somehow, so i reflashed the ecm, tuned it again, and then it shifted great... at the time my only tranny upgrades were transgo and T.C.
__________________
lmm with big tunes and stock tranny
Reply With Quote
  #7  
Old 10-25-2009, 06:14 PM
coker6303's Avatar
coker6303 coker6303 is offline
Keep Calm and Chive On!!
 
Join Date: Aug 2009
Location: Houston, TX
Truck: 08 2500 CCSB 4x4
Engine: LMM
Transmission: Automatic
Posts: 2,284

Default

Quote:
Originally Posted by dwax View Post
mine did the same thing (exactly) the first time i tune it with efi. turns out my old ppe was still hung in my computer somehow, so i reflashed the ecm, tuned it again, and then it shifted great... at the time my only tranny upgrades were transgo and T.C.
I have flashed it 3 times with the same program to be sure that everything is right. Might do it again just for grins.

Aren't the defuels in the TCM? That would mean the truck should still have the same defuel as before since I did not change the TCM tune right? All I did was pull 1 EFILive tune off the ECU and replace it with Rob's tune.
__________________
Russ

2015 Denali LML CC/SB - staying stock!!
2008 reg cab 2wd LMM - at Top Notch Garage getting some loving!! Shooting for low 11's to high 10's
2008 LMM CC/SB 4x4 - SOLD
S364.5FMW / batmo S480 twins 40% overs dual CP3
11.85 @ 113mph

Thank you to JoshH, emiller3, and blksmokelb7
Reply With Quote
  #8  
Old 10-25-2009, 07:06 PM
SteveFord's Avatar
SteveFord SteveFord is offline
What's Next?
 
Join Date: May 2008
Location: Iowa
Truck: CC
Engine: LLY
Transmission: Automatic
Posts: 1,368
Default

Possible torque managment kicking in. I wouldn't worry about it until you get your trans upgraded.
__________________
2009 llm
Reply With Quote
  #9  
Old 10-25-2009, 07:09 PM
Mike L.'s Avatar
Mike L. Mike L. is offline
Got Sheep?
 
Join Date: Aug 2006
Location: Disneyland, CA
Truck: 2011 Chev CC SB 4X4
Engine: 6.6
Transmission: Automatic
Posts: 10,895
Default

Defuel is ECM.
__________________
Shop 714 870 7300
Cell 310 918 9678

Tuned by Idaho Rob.
Reply With Quote
  #10  
Old 10-25-2009, 07:19 PM
The Neens's Avatar
The Neens The Neens is offline
BFD
 
Join Date: Aug 2006
Location: Valencia, Ca.
Truck: 2007 4WD CC/SB
Engine: LBZ
Transmission: Automatic
Posts: 5,181

Default

I'd give Rob a call, I'm sure he can make an adjustment to help you out...The 1st "big" tune I put in my LBZ acted this way, until it got some tweaking...
__________________
2007 GMC 4WD CC/SB...McRat EFI Live, Trans, Trans Cooler and C3 Clutch Oiling Mod by Mike L., SD sleeves, SoCal Diesel

2002 Chevy 2WD CC Dually...McRat EFI Live, Trans, Trans Cooler and C3 Clutch Oiling Mod by Mike L., SoCal Diesel



Next Taps party on ??-??-??

The sooner you fall behind, the more time you'll have to catch up...

Team Arrogance Founding Member

The Gerbil Clubs founding Member#1
"Gerbil Trainer for the Stars"
Reply With Quote
  #11  
Old 10-25-2009, 09:30 PM
x MadMAX DIESEL's Avatar
x MadMAX DIESEL x MadMAX DIESEL is offline
<<<< No Horsepower

 
Join Date: Dec 2008
Location: Lexington, Ky
Truck: EC/SB
Engine: LBZ
Transmission: Automatic
Posts: 6,753

Default

Are you hammmering down in Track/Haul ass mode? or just in overdrive? I'm gueing your TCm has got used to shifting in O/D if taht's the case it will take a bit to figure out the shift point's to shift in/.Most people put it inTH mode to hammer downa nmd only use that switch for getiin on it it
__________________
Ben
LBZ
12.26@108.8
7.78@87.7

Stock Turbo Puller
Quote:
Originally Posted by Utahski View Post
The absolute most obnoxious bumper sticker is one that's been around for awhile.....Obama-Biden '08
Quote:
Originally Posted by BgBlDodge View Post
Al gore invented driving the turbo.
Reply With Quote
  #12  
Old 10-26-2009, 06:16 AM
coker6303's Avatar
coker6303 coker6303 is offline
Keep Calm and Chive On!!
 
Join Date: Aug 2009
Location: Houston, TX
Truck: 08 2500 CCSB 4x4
Engine: LMM
Transmission: Automatic
Posts: 2,284

Default

I'll give Rob a ring this evening and pick his brain.

On the bright side, Rob's 110hp tune is friggin amazing! Very friendly around town and in traffic, very responsive but not explosive until WOT. Beats the crap out of my 80hp tune I was running before.
__________________
Russ

2015 Denali LML CC/SB - staying stock!!
2008 reg cab 2wd LMM - at Top Notch Garage getting some loving!! Shooting for low 11's to high 10's
2008 LMM CC/SB 4x4 - SOLD
S364.5FMW / batmo S480 twins 40% overs dual CP3
11.85 @ 113mph

Thank you to JoshH, emiller3, and blksmokelb7
Reply With Quote
  #13  
Old 11-04-2009, 07:46 AM
coker6303's Avatar
coker6303 coker6303 is offline
Keep Calm and Chive On!!
 
Join Date: Aug 2009
Location: Houston, TX
Truck: 08 2500 CCSB 4x4
Engine: LMM
Transmission: Automatic
Posts: 2,284

Default

UPDATE

IdahoRob fixed the problem, just a slight change in the tune fixed everything up. Shifts spot on!

Here's a mechanical problem that is developing. After I let the truck sit with the engine off for a couple of hours during the day or overnight (and I let my truck idle before driving) the light-mid shifts are drawn out. The engine revs a couple hundred rpms between shifts instead of snapping to the next gear like it should. It goes away after it is driven for a mile or so.

Here's the best I can explain it: apply light throttle revving to 2200rpms and the shift from 1-2 is triggered, the engine free revs (no trans resistance) an additional 200rpms to 2400 before pulling down into 2nd gear. It will do this whether you are in tow haul or normal. TCM tune is stock.

Again, it only seems to do this after the truck has set for a while. I'm going change the tranmission fluid again (changed 12000 miles ago with Amsoil). Truck has 37000 miles on it.
__________________
Russ

2015 Denali LML CC/SB - staying stock!!
2008 reg cab 2wd LMM - at Top Notch Garage getting some loving!! Shooting for low 11's to high 10's
2008 LMM CC/SB 4x4 - SOLD
S364.5FMW / batmo S480 twins 40% overs dual CP3
11.85 @ 113mph

Thank you to JoshH, emiller3, and blksmokelb7
Reply With Quote
  #14  
Old 11-05-2009, 12:41 PM
coker6303's Avatar
coker6303 coker6303 is offline
Keep Calm and Chive On!!
 
Join Date: Aug 2009
Location: Houston, TX
Truck: 08 2500 CCSB 4x4
Engine: LMM
Transmission: Automatic
Posts: 2,284

Default

logged 4 passes at WOT, during 3rd gear the revs are around 3400 rpms and trans slip rpms are up to 800. Remaining at WOT, it has no problem shifting and locking the converter (+/- 8rpms) in 4th gear. 1-2nd shifts are great, but 2-3 and while in 3rd something strange is going on.

any ideas
__________________
Russ

2015 Denali LML CC/SB - staying stock!!
2008 reg cab 2wd LMM - at Top Notch Garage getting some loving!! Shooting for low 11's to high 10's
2008 LMM CC/SB 4x4 - SOLD
S364.5FMW / batmo S480 twins 40% overs dual CP3
11.85 @ 113mph

Thank you to JoshH, emiller3, and blksmokelb7
Reply With Quote
  #15  
Old 11-05-2009, 02:10 PM
The Neens's Avatar
The Neens The Neens is offline
BFD
 
Join Date: Aug 2006
Location: Valencia, Ca.
Truck: 2007 4WD CC/SB
Engine: LBZ
Transmission: Automatic
Posts: 5,181

Default

Did you log it from rolling into the throttle, or from a boosted launch?
__________________
2007 GMC 4WD CC/SB...McRat EFI Live, Trans, Trans Cooler and C3 Clutch Oiling Mod by Mike L., SD sleeves, SoCal Diesel

2002 Chevy 2WD CC Dually...McRat EFI Live, Trans, Trans Cooler and C3 Clutch Oiling Mod by Mike L., SoCal Diesel



Next Taps party on ??-??-??

The sooner you fall behind, the more time you'll have to catch up...

Team Arrogance Founding Member

The Gerbil Clubs founding Member#1
"Gerbil Trainer for the Stars"
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 01:26 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
vB.Sponsors