NBMWSsix
02-17-2004, 08:48 PM
Q & A
This Q&A was created to answer basic questions that get asked regularly and sometimes go unanswered. This is your one stop information resource. If you see something or don't see something that you believe should be in here or is incorrect please post and I will do my best to research and update this. Thank you.
What symtoms did you have prior to rebuild?
Pops out of gear, hard to get in gear, gets stuck in gear, grinding in low rpms, grinding in high rpms, notchy shifting (when it shifts)
Wheres a good place to get a rebuild kit for the T-56.
D&D Performance (http://www.ddperformance.com/GM%20T56.htm)
Rockland Standard Gear (http://www.rsgear.com/)
The Gear Box (http://www.stores.ebay.com/id=22284527&ssPageName=L2)
My owners manual for 99 says dexron III, I see others referring to "GM synchromesh" or other synthetics or hybrids. Dealer parts guy never heard of it. Can you clear this up???
Here is the deal. Further research has determined that GM Synchromesh is safe for ALL T-56 transmissions. However, if you are seeing the strip, high rpm shifting in cooler climates may not be as smooth due to the viscosity mentioned below. HERE IS TEH PROOF! (http://www.ls2.com/forums/showthread.php?s=&threadid=13161) Others who work in the field will back me on this.
Pre '01 transmissions use paperlined blocker rings. Non-silicone based synthetic fluids will greatly shorten the life of your blocker rings by eating away at the paper fibers and you WILL have to have them replaced sooner. Post '01 trannys have carbon fiber lined blocker rings and it doesn't damage those. Your concern will be rust.
It also depends on how the car is driven. If it is a track machine stick with stock fluid, if it is a Sunday driver that hardly sees anything above 3,500 rpm then synthetic will be ok. Best bet is to just use what came in the tranny and leave it at that. M6's don't generate much heat or anything so basic fluid does fine regarding friction.
"GM synchromesh is not really a good fluid choice for any T56. It has a higher viscosity that can be detrimental to high speed shifting and would produce unacceptable shifts at lower temps( below 40 F)" -30THBIRD
GM Synchromesh is a Synthetic fluid. Synchromesh trans fluid p/n 12345349 $7.xx/qt. You will need 4 quarts if your tranny is bone dry. $30 dollars if you really want it.
Transmission shifting is notchy? What possibly causes this?
Partial notchiness is normal due to the design of the shifting patten design in side the tranny. It uses a spring and small ball bearing that moves between pits in a molded piece of steel. Notchiness can be one thing or a combination of things. Usually worn parts is the culprit. Most likely culprits are usually: throw out bearing, pressure plate, shift fork, gear blocker rings and rarely the shift links. Note if you are running synthetic and are on a pre 2001 trannmission or do not have carbon fiber blocker rings it is very possible that your paper lined blocker rings are deteriorating and are "sticking" to the gears.
Popping out of gear? What possibly causes this?
A bent shift fork causes this. If you still have a warranty take it to the dealer. There was a recall for this defective part (check the TSB). The original shift fork was aluminum and the replacement is steel.
No warranty you can get prices from local shops and get the steel replacement for about $49 from D&D from the link above.
TSB bent fork info:
Transmission Jumps Out of 3rd Gear (Replace 3-4 Shift Fork, 3-4 Synchronizer Assembly, 3rd Gear Blocker Ring and 3rd Speed Gear) #01-07-29-003A
Transmission Jumps Out of 3rd Gear (Replace 3-4 Shift Fork, 3-4 Synchronizer Assembly, 3rd Gear Blocker Ring and 3rd Speed Gear)
1999-2000 Chevrolet Camaro/1999-2000 Pontiac Firebird
with Manual Transmission (RPO MM6)
This bulletin is being revised due to a change in part numbers. Please discard Corporate Bulletin Number 01-07-29-003 (Section 07 - Transmission/Transaxle).
Condition
Some owners may comment that the transmission jumps out of 3rd gear.
Cause
Condition may be caused by inadequate travel of the 3-4 synchronizer assembly due to the 3-4 shift fork being out of specification or bent.
Correction
Notice
Please review the appropriate section of the Transmission Unit Repair Manual for correct disassembly and assembly instructions. When performing this bulletin, ALL parts listed need to be replaced. The condition originally occurs because of the 3-4 shift fork being out of specification or bent. This eventually results in damage to the synchronizer assembly, the blocker ring and the speed gear.
Replace the 3-4 synchronizer assembly, the 3rd gear blocker ring, the 3rd speed gear and the 3-4 shift fork.
Parts Information
Part Number Description Qty
12523207 3-4 Shift Fork 1
12523078 3/4 Synchronizer Assembly 1
12523186 3rd Gear Blocker Ring 1
12523077 3rd Speed Gear 1
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Description Labor Time
K2752 Gear -- R and R or Replace - 3rd Speed Gear Use Published Labor Time
Stuck in 4th or any gear for that matter?
You just pushed the housing to far and the slider keys are now partially out and probably at an angle preventing the housing to slide back. Try to just jiggle the shifter and work it back over. You may try with the car on or off. "Rocking" is also an option. You don't want to force it because you will just do more damage or break your slider keys or both.
What's that Grinding noise?
That noise is your snychronizer slider keys grinding against the sleeve of the synchro housing followed by the gear blocker rings grinding next. This is caused by two things, either hydraulics are not functioning correctly and not allowing the clutch to fully engage or disengage. The other reason is that your slider keys are either very worn or one or more of them are already broken causing your sleeve to align incorrectly.
What is TEH drill mod???
Teh drill mod is a minor modification done to the steel braided line for the master cylinder. It basically involves drilling out a small restrictor in one end of the line that GM had put in there to lessen the amount of fluid passing through. Details on how to do this can be found here: TEH drill mod (http://www.installuniversity.com/install_university/installu_pages/sophomore_year/drill_master_cylinder.htm)
What is TEH best way to bleed my clutch?
The Buschman's tutorial (http://mywebpages.comcast.net/buschman_007/Hawk/mcleod/clutchbleed.html) is the best method I have read about. I used it in my installation and have had no problems. Highly recommended.
Will a LT1/Viper T-56 fit in my LS1?
Yes and No. Yes almost any tranny will fit with MAJOR modifications and the right amount of money. Realistically? NO.
Check here for yourself. (http://www.rsgear.com/TREMEC/T56.pdf)
How do identify the internal gears of my T-56?
Drive members
1st..........39
2nd..........43
3rd..........37
4th(input gear)..........31
5th..........58
6th..........67
Rev..........14 Idler..........23
Driven members
1st..........17
2nd..........28
3rd..........33
4th..........36
Rev..........35
From front to back in the trans 4th,3rd,2nd,1st,6th,5th,rev.
How do other T-56's differ from the onein my LS1?
Application............................Input/Output Splines...........Ft/Lb.........1st...........2nd..........3rd..........4th...... .....5th.........6th..........Rev
GM Aftermarket......................26 / 27.............................400............2.97.........2 .07.........1.43........1.00.........0.80........0.62....... .3.28
5.0 Mustang Aftermarket..........10 / 31.............................400............2.97.........2 .07.........1.43........1.00.........0.80........0.62....... .3.28
'93 - '97 GM F-Body................26 / 27.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
'98 GM F-Body.......................26 / 27.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
Viper(also GM and Ford) (http://www.5speedtransmissions.com/vipert56conversion.html)...........26 / 30.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
'99 GM F-Body.......................26 / 27.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
4.6L Mustang.........................10 / 31.............................400............2.97.........2 .07.........1.43........1.00.........0.80........0.62....... .3.28
2003+ Viper*.........................26 / 30.............................550............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
*(TUET-1806 ONLY available through Chrysler)
This Q&A was created to answer basic questions that get asked regularly and sometimes go unanswered. This is your one stop information resource. If you see something or don't see something that you believe should be in here or is incorrect please post and I will do my best to research and update this. Thank you.
What symtoms did you have prior to rebuild?
Pops out of gear, hard to get in gear, gets stuck in gear, grinding in low rpms, grinding in high rpms, notchy shifting (when it shifts)
Wheres a good place to get a rebuild kit for the T-56.
D&D Performance (http://www.ddperformance.com/GM%20T56.htm)
Rockland Standard Gear (http://www.rsgear.com/)
The Gear Box (http://www.stores.ebay.com/id=22284527&ssPageName=L2)
My owners manual for 99 says dexron III, I see others referring to "GM synchromesh" or other synthetics or hybrids. Dealer parts guy never heard of it. Can you clear this up???
Here is the deal. Further research has determined that GM Synchromesh is safe for ALL T-56 transmissions. However, if you are seeing the strip, high rpm shifting in cooler climates may not be as smooth due to the viscosity mentioned below. HERE IS TEH PROOF! (http://www.ls2.com/forums/showthread.php?s=&threadid=13161) Others who work in the field will back me on this.
Pre '01 transmissions use paperlined blocker rings. Non-silicone based synthetic fluids will greatly shorten the life of your blocker rings by eating away at the paper fibers and you WILL have to have them replaced sooner. Post '01 trannys have carbon fiber lined blocker rings and it doesn't damage those. Your concern will be rust.
It also depends on how the car is driven. If it is a track machine stick with stock fluid, if it is a Sunday driver that hardly sees anything above 3,500 rpm then synthetic will be ok. Best bet is to just use what came in the tranny and leave it at that. M6's don't generate much heat or anything so basic fluid does fine regarding friction.
"GM synchromesh is not really a good fluid choice for any T56. It has a higher viscosity that can be detrimental to high speed shifting and would produce unacceptable shifts at lower temps( below 40 F)" -30THBIRD
GM Synchromesh is a Synthetic fluid. Synchromesh trans fluid p/n 12345349 $7.xx/qt. You will need 4 quarts if your tranny is bone dry. $30 dollars if you really want it.
Transmission shifting is notchy? What possibly causes this?
Partial notchiness is normal due to the design of the shifting patten design in side the tranny. It uses a spring and small ball bearing that moves between pits in a molded piece of steel. Notchiness can be one thing or a combination of things. Usually worn parts is the culprit. Most likely culprits are usually: throw out bearing, pressure plate, shift fork, gear blocker rings and rarely the shift links. Note if you are running synthetic and are on a pre 2001 trannmission or do not have carbon fiber blocker rings it is very possible that your paper lined blocker rings are deteriorating and are "sticking" to the gears.
Popping out of gear? What possibly causes this?
A bent shift fork causes this. If you still have a warranty take it to the dealer. There was a recall for this defective part (check the TSB). The original shift fork was aluminum and the replacement is steel.
No warranty you can get prices from local shops and get the steel replacement for about $49 from D&D from the link above.
TSB bent fork info:
Transmission Jumps Out of 3rd Gear (Replace 3-4 Shift Fork, 3-4 Synchronizer Assembly, 3rd Gear Blocker Ring and 3rd Speed Gear) #01-07-29-003A
Transmission Jumps Out of 3rd Gear (Replace 3-4 Shift Fork, 3-4 Synchronizer Assembly, 3rd Gear Blocker Ring and 3rd Speed Gear)
1999-2000 Chevrolet Camaro/1999-2000 Pontiac Firebird
with Manual Transmission (RPO MM6)
This bulletin is being revised due to a change in part numbers. Please discard Corporate Bulletin Number 01-07-29-003 (Section 07 - Transmission/Transaxle).
Condition
Some owners may comment that the transmission jumps out of 3rd gear.
Cause
Condition may be caused by inadequate travel of the 3-4 synchronizer assembly due to the 3-4 shift fork being out of specification or bent.
Correction
Notice
Please review the appropriate section of the Transmission Unit Repair Manual for correct disassembly and assembly instructions. When performing this bulletin, ALL parts listed need to be replaced. The condition originally occurs because of the 3-4 shift fork being out of specification or bent. This eventually results in damage to the synchronizer assembly, the blocker ring and the speed gear.
Replace the 3-4 synchronizer assembly, the 3rd gear blocker ring, the 3rd speed gear and the 3-4 shift fork.
Parts Information
Part Number Description Qty
12523207 3-4 Shift Fork 1
12523078 3/4 Synchronizer Assembly 1
12523186 3rd Gear Blocker Ring 1
12523077 3rd Speed Gear 1
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Description Labor Time
K2752 Gear -- R and R or Replace - 3rd Speed Gear Use Published Labor Time
Stuck in 4th or any gear for that matter?
You just pushed the housing to far and the slider keys are now partially out and probably at an angle preventing the housing to slide back. Try to just jiggle the shifter and work it back over. You may try with the car on or off. "Rocking" is also an option. You don't want to force it because you will just do more damage or break your slider keys or both.
What's that Grinding noise?
That noise is your snychronizer slider keys grinding against the sleeve of the synchro housing followed by the gear blocker rings grinding next. This is caused by two things, either hydraulics are not functioning correctly and not allowing the clutch to fully engage or disengage. The other reason is that your slider keys are either very worn or one or more of them are already broken causing your sleeve to align incorrectly.
What is TEH drill mod???
Teh drill mod is a minor modification done to the steel braided line for the master cylinder. It basically involves drilling out a small restrictor in one end of the line that GM had put in there to lessen the amount of fluid passing through. Details on how to do this can be found here: TEH drill mod (http://www.installuniversity.com/install_university/installu_pages/sophomore_year/drill_master_cylinder.htm)
What is TEH best way to bleed my clutch?
The Buschman's tutorial (http://mywebpages.comcast.net/buschman_007/Hawk/mcleod/clutchbleed.html) is the best method I have read about. I used it in my installation and have had no problems. Highly recommended.
Will a LT1/Viper T-56 fit in my LS1?
Yes and No. Yes almost any tranny will fit with MAJOR modifications and the right amount of money. Realistically? NO.
Check here for yourself. (http://www.rsgear.com/TREMEC/T56.pdf)
How do identify the internal gears of my T-56?
Drive members
1st..........39
2nd..........43
3rd..........37
4th(input gear)..........31
5th..........58
6th..........67
Rev..........14 Idler..........23
Driven members
1st..........17
2nd..........28
3rd..........33
4th..........36
Rev..........35
From front to back in the trans 4th,3rd,2nd,1st,6th,5th,rev.
How do other T-56's differ from the onein my LS1?
Application............................Input/Output Splines...........Ft/Lb.........1st...........2nd..........3rd..........4th...... .....5th.........6th..........Rev
GM Aftermarket......................26 / 27.............................400............2.97.........2 .07.........1.43........1.00.........0.80........0.62....... .3.28
5.0 Mustang Aftermarket..........10 / 31.............................400............2.97.........2 .07.........1.43........1.00.........0.80........0.62....... .3.28
'93 - '97 GM F-Body................26 / 27.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
'98 GM F-Body.......................26 / 27.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
Viper(also GM and Ford) (http://www.5speedtransmissions.com/vipert56conversion.html)...........26 / 30.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
'99 GM F-Body.......................26 / 27.............................450............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
4.6L Mustang.........................10 / 31.............................400............2.97.........2 .07.........1.43........1.00.........0.80........0.62....... .3.28
2003+ Viper*.........................26 / 30.............................550............2.66.........1 .78.........1.30........1.00.........0.74........0.50....... .2.90
*(TUET-1806 ONLY available through Chrysler)