Automatic Transmission 2-Speed thru 10-Speed GM Autos | Converters | Shift Kits
Sponsored by:
Sponsored by:

TC Lock/Unlock Ideas?

Thread Tools
 
Search this Thread
 
Old Aug 21, 2008 | 07:32 PM
  #1  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default TC Lock/Unlock Ideas?

I put in a Fuddle 4k stall a couple of weeks ago, and it randomly locks/unlocks on the highway. I got a tune and turned down the misfire tables, and it still did the same thing. So I took it back to the tuner, and he completely took out the misfire tables to test it. It still randomly locks/unlocks. I'm thinking it must be mechanical in the TC itself.

I was wondering if anyone else has any ideas or things to check before I start pulling the TC out to send it in for servicing. Thanks in advance for any suggestions.
Reply
Old Aug 21, 2008 | 08:13 PM
  #2  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

I remember doing a search awhile back about a way to test if it's a computer or mechanical issue, but I can't seem to find it now. It had something to do with an LED light and the trans connector. Does anyone know what I'm talking about?
Reply
Old Aug 21, 2008 | 08:27 PM
  #3  
performabuilt's Avatar
LS1Tech Sponsor
15 Year Member
Liked
Loved
Community Favorite
iTrader: (25)
 
Joined: Aug 2006
Posts: 10,854
Likes: 80
From: BLOOMSBURG PA
Default

Yes I wrote it .
1-go to radio shack get a 12 volt LED any color "not a light bulb" and some wire along with a blue side splicer connector . using the wire and splicer attach the negative side of the LED to the Tan wire with the black stripe in the harness that plugs into the trans, Then the positive side to 12 volts in the fuse box, Whenever the PCM commands lockup enable the LED will light up and whenever it turns it off the LED will go off then you will know if this issue is being commanded and wether its a tuning or converter issue. However It sounds more tuning related as converter generally as a rule cannot lock and unlock themselves randomly ,
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Reply
Old Aug 21, 2008 | 11:35 PM
  #4  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

Thanks for chiming in and reposting that test. What in the tuning, other than misfire tables, could cause it to lock/unlock randomly?
Reply
Old Aug 21, 2008 | 11:45 PM
  #5  
performabuilt's Avatar
LS1Tech Sponsor
15 Year Member
Liked
Loved
Community Favorite
iTrader: (25)
 
Joined: Aug 2006
Posts: 10,854
Likes: 80
From: BLOOMSBURG PA
Default

I am not a tuner so can not answer that but the test will show you which way to look
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Reply
Old Aug 22, 2008 | 07:57 AM
  #6  
lt170chevelle's Avatar
TECH Fanatic
iTrader: (2)
 
Joined: Jul 2006
Posts: 1,153
Likes: 1
From: BS,TX
Default

I was having similar problems with mine and just yesterday I lost 4th gear. I am thinking this was related to my problem...could be the same for you
Reply
Old Aug 22, 2008 | 10:35 AM
  #7  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

Thanks again for the help, performabuilt.

lt170chevelle: That sucks man. I hope that's not the case with mine. The tranny only has 36k miles and about 300 miles with the converter (none of it long distance). Good luck with yours as well.
Reply
Old Aug 22, 2008 | 02:39 PM
  #8  
omcar's Avatar
TECH Fanatic
iTrader: (10)
 
Joined: Jun 2006
Posts: 1,333
Likes: 0
From: Pennsylvania
Default

Perhaps the lock up is too low..I set mine at 48mph...
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

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

 Verdad Gallardo
story-1

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

 Pouria Savadkouei
story-2

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

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Aug 22, 2008 | 03:51 PM
  #9  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

My lock up is set at 40. Could that cause a problem? Another thing is when it does lock up it seems that it unlocks too easily. Giving it just a little throttle unlocks it no matter how gradual I increase the throttle. Even with cruise control on it will unlock just to maintain speed on the highway.
Reply
Old Aug 24, 2008 | 12:06 PM
  #10  
juniorsws6's Avatar
Teching In
 
Joined: Aug 2007
Posts: 15
Likes: 0
From: ruskin
Default

I had the same problem but my would rev up to 3000 rpms when the converter would unlock I replace the tps and everything went back to normal good luck bro
Reply
Old Aug 24, 2008 | 04:19 PM
  #11  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

Well I did the test Performabuilt suggested. The LED turned on and off at the appropriate times, so the computer and tuning are right on. With the light steadily on it would still go in and out of lock-up, so it must be a mechanical issue in the converter itself.
Reply
Old Sep 9, 2008 | 06:36 AM
  #12  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

Well the Fuddle converter went out on me. I put the stock converter back in. The Fuddle had pieces rattling around in it and the converter and tranny were full of metal shavings. I replaced the filter and fluid, ran it a couple of minutes, changed the fluid and filter again and took an air compressor to the tranny cooler. I took it on a short highway test with the stock converter. It is slipping and the RPMs went up to 3-4K with just moderate throttle at about 70mph. The LED light showed lock up was being commanded.

Could it be something in the transmission? I installed a Transgo HD2 shift kit (w/o the internal parts) at the same time as the Fuddle converter. I also shimmed the converter when I put that in.

I'm not sure what to do now. Anyone have any ideas or suggestions? Thanks.

Last edited by usmc320; Sep 10, 2008 at 12:10 AM.
Reply
Old Sep 9, 2008 | 09:41 AM
  #13  
performabuilt's Avatar
LS1Tech Sponsor
15 Year Member
Liked
Loved
Community Favorite
iTrader: (25)
 
Joined: Aug 2006
Posts: 10,854
Likes: 80
From: BLOOMSBURG PA
Default

Unfortunately when a converter fails and metal goes through the trans from it ,The metal and debris end up in the trans lube circuit and the valve body clogging filters in the solenoids etc, While you may be able to remove the valve body and clean it there is no way short of tearing down the trans to get the debris out of the input shaft and planets lube holes which may become clogged. It is likely you may end up with a trans failure to boot soon
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Reply
Old Sep 9, 2008 | 10:53 AM
  #14  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

Oh I forgot to mention - It drives fine at lower speeds, but at highway when it should be locked up it seems to slip.

performabuilt - Thanks for the input. I was afraid that may be the case. I've been planning on a 4l80e swap sometime in the future. Guess I should consider getting together parts soon.

I am going to change the fluid and filter 1 more time to try to get any remaining debris out that is worked loose. I will drop the valve body while I'm in there.
Reply
Old Sep 9, 2008 | 10:56 AM
  #15  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

BTW When I go 4l80e I wanted to put a used one in for now to get the car going again. I hear it should be more than adequate in stock form. Should I do the Transgo shift kit as well or not bother. I plan on running a Yank PY3600 converter.
Reply
Old Sep 9, 2008 | 11:12 AM
  #16  
performabuilt's Avatar
LS1Tech Sponsor
15 Year Member
Liked
Loved
Community Favorite
iTrader: (25)
 
Joined: Aug 2006
Posts: 10,854
Likes: 80
From: BLOOMSBURG PA
Default

You would want the shift kit the 80e stock shifts are kinda lazy
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Reply
Old Sep 10, 2008 | 11:37 AM
  #17  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

Do you carry the transgo shift kit for the 4l80e?
Reply
Old Sep 10, 2008 | 12:07 PM
  #18  
performabuilt's Avatar
LS1Tech Sponsor
15 Year Member
Liked
Loved
Community Favorite
iTrader: (25)
 
Joined: Aug 2006
Posts: 10,854
Likes: 80
From: BLOOMSBURG PA
Default

No I a afraid at this time we do not carry parts at all
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Reply
Old Oct 13, 2008 | 04:12 PM
  #19  
usmc320's Avatar
Thread Starter
12 Second Club
iTrader: (3)
 
Joined: May 2008
Posts: 229
Likes: 0
From: VA
Default

Originally Posted by performabuilt
Yes I wrote it .
1-go to radio shack get a 12 volt LED any color "not a light bulb" and some wire along with a blue side splicer connector . using the wire and splicer attach the negative side of the LED to the Tan wire with the black stripe in the harness that plugs into the trans, Then the positive side to 12 volts in the fuse box, Whenever the PCM commands lockup enable the LED will light up and whenever it turns it off the LED will go off then you will know if this issue is being commanded and wether its a tuning or converter issue. However It sounds more tuning related as converter generally as a rule cannot lock and unlock themselves randomly ,
One more question, Performabuilt or anyone else who may know. I did a 4l80e conversion using the stock PCM. This led that I wired no longer works when lockup is engaged. Is the 4l80e lockup command wire different than the 60? I am using the Speartech harness adapter, so I thought it would be the same wire. Guess not.

I'm not having any lockup issues, but was just curious if this changed.
Reply
Old Oct 13, 2008 | 05:11 PM
  #20  
performabuilt's Avatar
LS1Tech Sponsor
15 Year Member
Liked
Loved
Community Favorite
iTrader: (25)
 
Joined: Aug 2006
Posts: 10,854
Likes: 80
From: BLOOMSBURG PA
Default

Yes lockup uses a different wire with the 80E not sure about the colors on the speartech harness though
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Reply



All times are GMT -5. The time now is 10:45 PM.

story-0
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-1
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-2
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-3
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-4
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
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE