LS4 Performance Grand Prix GXP | Monte Carlo SS | Impala SS | LaCrosse Super

Tap Shift question

Thread Tools
 
Search this Thread
 
Old Sep 19, 2011 | 01:29 PM
  #1  
06gpgxp's Avatar
Thread Starter
Teching In
 
Joined: Feb 2011
Posts: 11
Likes: 0
Default Tap Shift question

I'm wondering if it's normal when in tap shift the transmission doesn't shift into fourth gear? I can shift from 3 to 4 with no rpm change and no overdrive. When the dic says 4 it's still in third gear. When in drive transmission shifts into 4. This is all at highway speed 55+.
Reply
Old Sep 20, 2011 | 05:09 PM
  #2  
redlightrampage's Avatar
On The Tree
iTrader: (2)
 
Joined: Apr 2011
Posts: 196
Likes: 0
From: MI
Default

Nope! Definitely not normal.
Reply
Old Sep 20, 2011 | 06:48 PM
  #3  
06gpgxp's Avatar
Thread Starter
Teching In
 
Joined: Feb 2011
Posts: 11
Likes: 0
Default

I didn't think so. I've searched the LS4 threads for something similar to this but didn't have any luck. Transmission seems to be shifting fine when not in tap shift. About 10k miles ago i had a new torque converter installed along with new filter and fluid. It's an '06 with 53k on it. I've also had the stability, traction control and abs warnings come on whenever they feel like it. They will come on one day and the next day it will be fine.
Reply
Old Sep 20, 2011 | 07:16 PM
  #4  
Hawkins04's Avatar
TECH Fanatic
iTrader: (4)
 
Joined: Feb 2010
Posts: 1,467
Likes: 0
From: Lawrencevile, GA
Default

hows the battery connections?
Reply
Old Sep 22, 2011 | 09:39 AM
  #5  
redlightrampage's Avatar
On The Tree
iTrader: (2)
 
Joined: Apr 2011
Posts: 196
Likes: 0
From: MI
Default

There is a TSB on the sensor, I had mine replaced about 3 months ago. I lost my 3-2, 2-1 down shift capability in TapShift right before I had the trans replaced. I wish I could get my hands on some solid TapShift drawings/schematics I could probably help more.
Reply
Old Sep 22, 2011 | 11:14 AM
  #6  
06gpgxp's Avatar
Thread Starter
Teching In
 
Joined: Feb 2011
Posts: 11
Likes: 0
Default

I just had the car into the GM dealership and they said that when its in tap shift mode it locks out overdrive and gears 1-3 only work in tap shift.
There were codes for my stability, traction control and abs but when i brought it in the warning light wasn't on so they couldn't pinpoint the real problem which i'm guessing its probably the hub assembly? So the next time the warning comes up I need to bring it to the dealer i guess.
Reply
Old Sep 22, 2011 | 11:26 AM
  #7  
redlightrampage's Avatar
On The Tree
iTrader: (2)
 
Joined: Apr 2011
Posts: 196
Likes: 0
From: MI
Default

Locks out overdrive? I'm calling BS on this one. I can shift into 4th just fine. Are you tuned? I can pull a stock 06' GXP tune from HPtuners and look at the shift tables.
Reply
Old Sep 22, 2011 | 12:02 PM
  #8  
06gpgxp's Avatar
Thread Starter
Teching In
 
Joined: Feb 2011
Posts: 11
Likes: 0
Default

No tune, completely stock. Going down the higway at 60 mph and shift it to tap shift and it kicks up into 3rd. The DIC says its in 4th? Then i shift from tap to drive and it shifts into 4th. I rarely use tap shift but noticed it the other day.
Thanks for all your help!
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

10 Reasons Daily Driving a Swap Project SUCKS! (& 1 Reason to Do It Anyway)

 Michael S. Palmer
story-1

6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

 Brett Foote
story-2

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-3

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-4

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-5

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-6

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-7

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-8

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-9

Top 10 Most Powerful Chevy Trucks Ever Made!

 
Old Sep 22, 2011 | 04:16 PM
  #9  
redlightrampage's Avatar
On The Tree
iTrader: (2)
 
Joined: Apr 2011
Posts: 196
Likes: 0
From: MI
Default

I checked out you TapShift tables...Check out the attachment, view in paint if it is too small. This is the table that governs your TapShift shift points part throttle. If you were going 60 and shifted in 4th gear it should have shifted...there are 4 -> 3 downshift stipulations but those end at 50 MPH and you would have had to of been on it quite a bit to exceed the TPS %. I'm assuming they put those there to prevent people from going WOT in 4th gear under heavy load which isn't good for the trans.

Could possibly be a shift solenoid, could data log and check certain trans properties to see what is going on internally. Nothing in your tapshift part throttle tables is different from my 08'. GM is full of it!
Attached Thumbnails Tap Shift question-tapshift.jpg  
Reply




All times are GMT -5. The time now is 07:04 AM.

story-0
10 Reasons Daily Driving a Swap Project SUCKS! (& 1 Reason to Do It Anyway)

Slideshow: 10 reasons daily-driving a swap project might not be for you. Or is it?

By Michael S. Palmer | 2026-06-17 09:39:05


VIEW MORE
story-1
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-09 14:55:56


VIEW MORE
story-2
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-06-18 10:26:23


VIEW MORE
story-3
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-4
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-5
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-6
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-7
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-8
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-9
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE