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Thread: T-56, fluids,mods,answers. LS2 location

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    Questions, Problems? T-56, fluids, mods, answers. Read this first!

    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
    Rockland Standard Gear
    The Gear Box


    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! 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

    What is TEH best way to bleed my clutch?
    The Buschman's tutorial 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.

    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)...........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)
    Last edited by NBMWSsix; 06-02-2004 at 12:46 AM.

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    Gonna rebuild your own tranny? Step-by-step right here:

    The tranny used was previously rebuilt by who knows? This rebuild was my first. It was very confusing at first. I used the T-56 service manual and the Shifting Six with Confidence article used High Performance Pontiac. It takes a few hours from start to finish if you know what you are doing. If not take it slow and place pieces in sequence the way you take them off on a separate table. I also recommend taking pictures with a digital camera to see how things go back together in case you don't remember. I could only work on it on weekends so I would have to look at the pics and the service manual. Printing out this thread wouldn't be bad idea either.
    NOTE: If you dis-assemble the synchro assembly(slider&hub) as pictures indicate, be sure to re-assemble them the same way. These are marked with a laser marking to show the original orientation. This will insure the proper fit of the parts. Excessive loosness (rock) can cause gear jump out and general shift complaints.
    Handling of the parts with the bearings installed requires some care, too. It is very easy to bump the mainshaft pocket bearing and not know of the damage untill you do a drive test. A little extra care can save some serious strings of foul language later.
    Lastly , keep every thing clean. Even simple lint / threads from rags can be a detriment to a favorible result.

    Tools needed:
    When it comes to tools with the exception of the gear puller I fabricated I bought quality tools. IT will save you a lot of time if you have the right tools.
    SOLD WORK TABLE With a good sized opening or separation since the tranny will be verticle for most of the process. The opening is for the input shaft of the transmission.
    SNAP RING PLIERS for both styles - Slant tipped and hole tipped. The snap rings used on the transmission are heavy duty and WILL either bend or break your "El Cheapo" brand snap ring pliers. Craftsman or a good name brand will do well. Trust me on this that was $4.99 down the drain.
    GEAR PULLER - Professional ones range from $80 to $200. I made my own for about $20. I got the largest 3-sided gear puller I could find for like $9. It was too short so I went to Home Depot and got a couple of metal strips that were the same width and thickness, cut them to about 12 inches in length. I then drilled holes spaced about 1 inch apart on one end to make it adjustable length. It worked perfect.
    HOLLOW PIPE large enough to fit over the mainshaft.
    HAMMER Used when you need a little extra effort. Not to be used out of frustration.
    SMALL OR MEDIUM GEAR PULLER to remove teh speed sensor and the 3-4 synchronizer hub.
    T-30 OR T-40 TORX BITS to remove teh two torx screws on the side of the case.
    Here are the speciality tools:


    Parts Replaced: - 1-2 Synchro keys, 3-4 shift fork, 3-4 synchro keys, 3-4 gear blocker rings, C-springs for both housings.

    Synchro assembly from the T-56 manual:


    C springs for the inner synchro housing. The gear blocker rings were also showing signs of wear so those were replaced as well. Worn blocker rings with paper like linings, these were replaced.


    First thing that should have been done is to drain most of the fluid out of the tranny for two reasons. When you start lowering the tranny it will start to leak out the rear seal and all over you. The other reason is the tranny weighs about 100 lbs bone dry so you can do yourself a favor by getting rid of that extra weight.

    This picture I am removing the rest out of the rear part of the case so that it just doesn't make a mess. I put it in the bucket to inspect what settles at the bottom, metal shavings, broken pieces, etc.


    Next remove the two bolts off the front of the transmission that hold on the slave and remove the slave. You will notice that there are several bolts that may be hard to notice because of clutch disc dust. Remove all but two of these, on opposite ends from each other. Loosen these two leaving about 1/4" between them and the plate.
    These bolts are circled in red. Should be 11, but I could have missed one.


    Next place your bucket under the front plate. Using a large screwdriver or similar tool we want to pry open the plate from the case using the pry spots. You may need to used the hammer to get it started. Be careful not to gouge the surface where the plate and cover come together. These trannys don't used gaskets and you will end up with a pemanent leak. They cannot be machined either because things won't line up inside.
    Pictured here:


    After removing all the fluid re-tighten the bolts (hand tight) and turn the tranny upright. Using a punch or similar you will want to remove the shifting saddle pin. Then slide off the saddle.
    Last edited by NBMWSsix; 04-27-2004 at 03:42 AM.

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    Remember to tap the pin partially back in to the saddle afterwards or you will risk losing it.


    Using hand ratchet and socket you will want to hand loosen the bolts holding the rear casing on. After loosening them you can use an air ratchet to finish removing them.


    Using your screwdriver locate the pry spots and separate the rear casing from the main body. Keep in mind to not scratch the surfaces.


    Then after you have separated them simply lift off the rear casing.







    From here the case magnets will be visible. If there is debris larger than what is pictured, that could be one sign that something more serious is going on inside.


    First thing to do is remove the rear seal that will be on the mainshaft. Below it will be your first slant tip snap ring. Remove this and use a gear puller to remove the speedo sensor pictured below.


    Next remove the two snap rings and bearing to remove the reverse gear.


    Next remove the snap ring holding the reverse synchro housing in place.

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    Before attempting to remove the reverse synchro assembly don't forget to take off the snap ring holding the reverse shift fork on the shift rail.



    Now it's time to bring out the big boys! Grab the super duper gear puller and set it up to its longest setting (if you made one like I did) to reach the 5-6 gear. Using a hand ratchet and socket, start to slowly remove it and after a while it should slide off freely.


    It's sort of difficult to see but in this picture there is another snap ring that must be removed before taking out the back section of the countershaft.


    Now slide out the fork and the countershaft together.


    Next using a T-30 torx bit, remove the alignment screws on the side of the case.


    Now you are ready to remove the main casing off of the front plate. When doing this keep and eye on the shifting pattern piece(circled in yellow), when it comes off the rail it will want to pop off due to the spring and ball bearing that is inside it. Be careful not to lose it.


    Now inside the front of the main case we have the 1-2 and 3-4 gear and related components. You can lift the mainshaft and the shift rail together to separate the forks and rail from the mainshaft. You can then set the mainshaft back and remove teh little rubber seal holding the large race bearing. Remember to take it out first. That is the only thing hold the bearing in place.


    Here is what we are looking at. On the left is the mainshaft shiftrail. Then the mainshaft in the middle with 3-4 assembly on the bottom (blue) and the largest assembly is the 1-2 near the middle of the mainshaft (yellow). To the right is the countershaft (red).
    Last edited by NBMWSsix; 06-15-2004 at 04:08 AM.

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    I inspected the parts according to the service manual and found all them to be fine except the pieces replaced.
    I replaced the 3,4 shift fork with a steel one. I replaced the 3,4 synchro housing along with the keys and C-springs. There was also a plastic spacer behind the third gear that had partially melted into the 3,4 synchro housing. This was replaced by a steel spacer. If you have a 2000 or newer you already have this steel spacer.

    Oh yeah DO NOT remove bearings unless you need to replace them. All the parts slide over them so don't waste your time. They are a PITA!

    Front plate and the infamous 3,4 synchro still on the mainshaft. The snap ring on the plate on the left has to be removed prior to removing the 3-4 synchor hub. Using the smaller gear puller you can pull off the hub after you have removed the outer synchro sleeve, keys, C-springs.


    Here is little description of what some of the parts look like (don't be scurred):


    Final Product...it's....so...beautiful!


    The famous T-56 service manual with custom cover made by me.


    I also re-tightened the snap rings using a hammer and banging on them to close them a little so they would be tight on the shafts.
    NOTE: "You discuss"resizing " snap rings . This is generally a bad practice. If they require resizing, it most likely due to over-expansion. It is a better practice to use new rings. This allows only one expansion ( for install) an reduses the risk of a cracked ring developing into a broken ring down the road.It is most critical , though , that one is sure all rings are fully seated in their respective groove.It is easy to mix the snaprings as well so to lay them out carefully is also a good move." -30THBIRD

    After reassembly, you should seal the case with silicone. Do not put tranny fluid into the tranny until the silicone is dry.

    Results:Prior to install I went thru the gears with the shifter and everyting was very smooth. I also did the McLeod master bleed and Thanks to Buschman's Tutorial the clutch is very solid.
    The tranny was installed Monday. It takes 4 quarts of fluid. I started up the car and there was some noise from the tranny until everyting got covered in fluid then it quieted down. I took it for a test drive and every gear was smooth. Took it out on a very quiet road and let loose. 1st, 2nd breaks the tires loose easily. 3rd has a very pronounced bark. 4th,5th,6th very smooth. Took it up to about 120mph no problems. So the sleeper has awakened again...

    P.S. If anyone is going to attempt this I can give u some pointers or answer questions to the best of my knowledge. Overall it was a great learning experience and not as difficult as I expected. I am glad I decided to do it.

    Credits: Thanks to LS2.com (30thbird/JMWS62001), Installuniversity, High Performance Pontiac Magazine, Buschman's Tutorial, Rockland Standard Gear, and God because only he knows how I managed to figure this out by myself.
    Last edited by NBMWSsix; 06-15-2004 at 04:20 AM.

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    I put gm Synchromesh in my car and the shifting got better? So your telling me, its gonna kill my tranny?

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    Originally posted by MIKE2000Z28
    I put gm Synchromesh in my car and the shifting got better? So your telling me, its gonna kill my tranny?
    Did you buy your car new? Are you the only owner? Where you live and the climate makes a difference. Warmer temps don't affect the shifting very much, and it may seem smoother for now. It also depends on how you drive it. If you drive it hard I see you needing a rebuild sooner. With synthetics the colder temps is where it will affect shifting more noticeably.

    GM Synchromesh is safe choice for your tranny.

    EDIT: I did some research and have updated the Q&A.



    Clicky!
    Last edited by NBMWSsix; 03-10-2004 at 01:02 AM.

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    I have copied this thread into the How to forum. You may unsticky this thread. I am changing the links in the other thread to point to pictures on this site.


    This is awsome!


    Elmer

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