Manual Transmission T56 | T5 | MN12 | Clutches | Hydraulics | Shifters

What in the world is going on inside this T56

Thread Tools
 
Search this Thread
 
Old Aug 21, 2013 | 03:53 PM
  #1  
chawin's Avatar
Thread Starter
Staging Lane
 
Joined: May 2012
Posts: 83
Likes: 0
From: Hugo, MN
Default What in the world is going on inside this T56

Hey guys,

I have a 2000 WS6 with a 6 speed (T56).
One day driving the car Just driving it like an old man in his station wagon. I Went to shift for 6th and had a little grind... Odd cause its always shifted flawlessly. Next time I go for 6th gear get a small grind then it would go in and would pop out if I let off the gas.... Started getting bad fast and would have to hold it in 6th. Now when I go for 6th it wont even grind... Im just shifting into an empty gate... nothing there at all. Now 5th gear is there and goes in flawlessly from 4th but when on the gas its all good... but when you let off the gas the stick moves forward about an inch and a half and sometimes will pop out of 5th and when you get back on the gas the stick moves back that inch and a half. I stuck my hand through the shifter boot hole and put my hand on the tranny and the tranny doesnt move at all (I have poly motor mounts) All the movement is in the stick and internally. 1-4 and reverse are flawless but 5 and 6 are shot and 5 has its days numbered.

My question is what is going on here? I understand that 5th and 6th are on the same main shaft but what is moving in there to cause that much movement under load or no load. Is the gear pack on the main shaft moving? Is the main shaft moving?

I had read somewhere that 5th/6th can be replace/repaired without pulling everything apart? Truth? Or if since someone would already be in there (either myself or a transmission tech) would it be worthwhile to do any modifications that are a known common failure? I guess my biggest deal right now is what does it sound like is going on with my 5th and 6th? If you need more info let me know
Reply
Old Aug 21, 2013 | 09:21 PM
  #2  
jmd's Avatar
jmd
TECH Addict
20 Year Member
Photogenic
Liked
Loved
iTrader: (4)
 
Joined: May 2002
Posts: 2,620
Likes: 36
From: T56th Street, Aridzona
Default

https://ls1tech.com/forums/16471799-post3.html
Reply
Old Aug 22, 2013 | 12:13 PM
  #3  
chawin's Avatar
Thread Starter
Staging Lane
 
Joined: May 2012
Posts: 83
Likes: 0
From: Hugo, MN
Default

Thank you for the reply.

Very odd how it just very randomly happened. Wasnt hot rodding it or fast shifting or anything. Just gingerly driving along. I could see if I was slamming gears but I wasnt.

So to you guys this sounds more like a shift fork issue rather than the actual gears themselves. Although the synchros may have been damaged but beyond that not so much the gears sliding up and down the mainshaft? (my understanding is they are pressed on and may become "unpressed")

Just weird how the shift lever has so much movement depending on how much load is added to the driveline. I just dont understand what else is moving in there if the gears themselves arent moving.
Reply
Old Aug 22, 2013 | 03:21 PM
  #4  
1999Firehawkls7's Avatar
Launching!
iTrader: (3)
 
Joined: Aug 2013
Posts: 228
Likes: 0
Default

Take a T56 apart once or look at pics....theres alot going on in there lol

One of the T56 out of a Lt1 we had apart had a broken fork in it, the 5-6 fork is half as thick as the rest.....this is to make room for the extra (6th) gear in the gear box

Half as thick mean half as strong.....thats why ya never bang on 5th or 6th, not saying ya did and thats what caused it neither
Reply
Old Aug 22, 2013 | 03:48 PM
  #5  
BMR Sales2's Avatar
LS1Tech Premium Sponsor
iTrader: (40)
 
Joined: Nov 2008
Posts: 3,451
Likes: 20
From: Seffner, FL
Default

It could be a number of things. I have seen similar symptoms happen when the splines between the mainshaft and 5th/6th cluster get wore down and build up too much tolerance. The only way you are really going to find out what is going on is to tear the transmission down at least partially.
__________________
Glenn ***
Sales Tech
www.bmrsuspension.com
813.986.9302


Find a Quality alignment shop near you!
Reply
Old Aug 23, 2013 | 09:45 AM
  #6  
chawin's Avatar
Thread Starter
Staging Lane
 
Joined: May 2012
Posts: 83
Likes: 0
From: Hugo, MN
Default

Right, I will end up digging into it real soon. Just before that was trying to get a little insight of what could be the cause or what is going on. I have looked at a T56 that was cut in half and played with it for about a half an hour just looking at how everything was working in there. Though this was quite awhile ago now. At any rate the broken fork or broken pads makes sense since the shift lever cant go far enough to fully engage sixth. But then it doesnt make sense that the shift level moves back and forth in fifth gear depending on load put on the engine... That to me would indicate that 5th is moving on the mainshaft when it should not due to the pressed on fit. That to me makes sense right now until I actually tear into it but I could be very wrong. Ive never tore into one so was thinking one of you T56 veterans would have an idea. Thanks for the help and the suggestions so far guys.
Reply
Old Aug 30, 2013 | 10:54 AM
  #7  
chawin's Avatar
Thread Starter
Staging Lane
 
Joined: May 2012
Posts: 83
Likes: 0
From: Hugo, MN
Default

Just a little update if this helps for anyone that would have an idea what is going on. 1-4 shifts fantastic like usual. 5th still goes in flawlessly but depending on the if im giving the tranny load or not it will pop out under no load unless I hold it with a small amount of pressure. The new news is that if I move the leather boot out of the way and put it in 6th and hold the stick and slowly let the clutch out it will go into 6th and stay in 6th... absolutely no movement in the stick no matter if im giving it WOT or not on the throttle at all and it does not pop out. But to get it into 6th you have to pull the stick back so far backward that it interferes with the console like where the ash tray is. We still leaning toward it being the shift fork as educated guesses?

I will be getting it pulled out and torn apart but in the mean time it is interesting to find out what is really going on in there and what you T56 educated guys come up with for explanations. Thanks again!
Reply
Old Aug 30, 2013 | 11:25 AM
  #8  
jmd's Avatar
jmd
TECH Addict
20 Year Member
Photogenic
Liked
Loved
iTrader: (4)
 
Joined: May 2002
Posts: 2,620
Likes: 36
From: T56th Street, Aridzona
Default

Post 2.

Get 'er pulled. :beer:
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

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

 Pouria Savadkouei
story-1

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

 Verdad Gallardo
story-2

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-3

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

 Verdad Gallardo
story-4

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

 Pouria Savadkouei
story-5

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

 Verdad Gallardo
story-6

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-7

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-8

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-9

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

 Verdad Gallardo
Old Oct 21, 2013 | 06:31 PM
  #9  
68BBChevelle's Avatar
TECH Apprentice
iTrader: (12)
 
Joined: Oct 2011
Posts: 381
Likes: 0
From: Denton Md
Default

Having same problems what did you come up with?
Reply
Old Oct 26, 2013 | 01:33 PM
  #10  
68BBChevelle's Avatar
TECH Apprentice
iTrader: (12)
 
Joined: Oct 2011
Posts: 381
Likes: 0
From: Denton Md
Default

updates ....
Reply




All times are GMT -5. The time now is 11:20 AM.

story-0
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 | 2026-05-28 11:05:11


VIEW MORE
story-1
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-2
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-3
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-4
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-5
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-6
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-7
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-8
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-9
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