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Thread: Synthetic fluid in my T-56?

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    NBMWSsix's Avatar

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    Feb 2004
    Austin, Texas

    Can I run a synthetic fluid in my T-56? Maybe. Look inside.

    Mods can we make this a sticky.

    After much reasearch I believe the Synthetic Fluid question is resolved. Can I run synthetic fluid in my T-56? Yes and no. There are two types of synthetic fluids. Hygroscopic and Non-hygroscopic.

    Confused? Good. Here's the definition:

    One entry found for hygroscopic.
    Main Entry: hy∑gro∑scop∑ic
    Pronunciation: "hI-gr&-'skš-pik
    Function: adjective
    Etymology: hygroscope, an instrument showing changes in humidity + 1-ic; from the use of such materials in the hygroscope
    1 : readily taking up and retaining moisture
    2 : taken up and retained under some conditions of humidity and temperature <hygroscopic water in clay

    In other words it absorbs water easily

    Here is the obvious point. Water will most defintely damage any paper product. If the synthetic fluid you use is not silicone based then it will absorb water and saturate the PAPER lined blocker rings and cause them to deteriorate sooner.

    If the synthetic fluid is silicone based then the way the transmission performs will be based on how it is driven and the climate. Damage should not be because of the fluid.

    The newer '01-'02 transmissions have the carbon fiber lined blocker rings.

    One entry found for carbon fiber.
    Main Entry: carbon fiber
    Function: noun
    : a very strong lightweight synthetic fiber made especially by carbonizing acrylic fiber at high temperatures

    "Carbon fiber is a high strength, high stiffness synthetic fiber that is manufactured by heating, oxidizing, and carbonizing polyacrylonitrile polymer fibers. The resulting carbon fibers are typically molded into high strength composite materials for structural applications or are used in their pure form for electrical and friction applications. In friction applications, carbon fiber is used to create materials that can withstand extremely high temperature coupled with brutal abrasive wear. Carbon fiber composites have amazing structural properties. Carbon fiber composites are ten times stronger than steel, yet are still five times lighter. In comparison to aluminum, carbon fiber composites are eight times stronger, two times stiffer, yet still 1.5 times lighter. Carbon fiber composites have superior fatigue properties to all known metallic structures, and when coupled with the proper resins, carbon fiber composites are one of the most corrosion resistant materials available."

    Carbon fiber is basically impervious to water damage and very rugged. It also explains why the newer transmissions can run synthetic fluid with out any side effects. However, remember that water and metal are enemies and that running a non-silicone synthetic in ANY T-56 will eventually cause problems (Hint: rust).

    Examples of carbon fiber and synthetic fluids used in other environments.

    Carbon Fiber in foundation repair,
    has developed a Carbon-fiber/Kevlar grid strap reinforcement system, designed to stabilize foundations that have fractured or bowed due to soil pressure, water damage or other causes.
    Our reinforcement system arrests any further movement without costly excavation, tiebacks, or steel I-beams. We guarantee our grid straps for the life of your home.

    Fortress Carbon-fiber/Kevlar grid straps have been thoroughly tested and proven to be the best solution on the market today."

    Synthetics in metalworking.
    "Synthetic metalworking fluids lend themselves to grinding and light duty machining. Synthetics work great for grinding because they allow for swift settling of the small fines created during grinding. Grinding fluids should be cleaner than machining fluids because they cover a larger work area, and can splash more than a machining operation. Whereas water-soluble oils will absorb tramp oils, synthetics will typically reject the oils, allowing them to be skimmed from the surface of the metalworking fluid. This feature allows synthetics in some applications greater longevity in the sump. Many synthetics work well for machining of all metals, and some of the newer and more expensive synthetics can approach the tool life of water-soluble oils. The disadvantage of synthetics is that some components such as lubricants and rust preventives can be "used up" before the rest of the metalworking fluid."

    Synthetic Fluids by CitroŽn
    The early fluid -- LHS 2 -- is a synthetic fluid. The vast majority of brake fluids are and always have been synthetic. They are descendants of fluids employed in the days when the only rubbers available for seals, etc., were incompatable with petroleum oil. The biggest disadvantage with synthetic fluid is that it is hygroscopic i.e. it absorbs water easily. CitroŽn, leading the way yet again, came up with a mineral fluid -- LHM -- which is not hygroscopic, over 30 years ago. Obviously, there were other improvements with the advent of LHM.

    Below is part of a chart, courtesy of BP, showing the differences between the specifications of LHS 2 versus LHM:
    Properties....................Units.................LHS2.... ............LHM
    Desity 15*
    Flash Point..................*C......................99........... ..........135
    Viscosity Index......................................256.............. .....285

    GM Synchromesh is safe to use in ALL T-56's. It is Silicone based.
    The information presented here is gathered from the documents listed in the References section below.

    Pennzoil-Quaker State Synchromesh is a unique transmission and transaxle fluid that is not API "GL" rated. It has an approximate gear oil grade of about SAE 80W and can be used when temperatures range from -40ļF (-40ļC) to 300ļF (150ļC). According to Pennzoil's product description it is "formulated with high quality paraffinic base stocks, a fluidity modifier, multifunctional performance additives, corrosion inhibitors, a foam suppressor and a shear stable viscosity index improver additive. It provides excellent oxidation stability, low temperature performance, excellent synchronizer performance and compatibility with yellow metals, such as bronze, brass and copper components found in manual transaxles and transmissions." This description makes Synchromesh suitable for use in some transaxles or transmissions where GL-4 gear oils are specified.

    A post on the message board at found Synchromesh to consist of a 5W30 non-detergent oil with a friction modifer and an EP (extreme pressure) additive. It is made under contract for General Motors by Pennzoil (APC 3378) or by Texaco (Code 1874 MTX Fluid).

    According to Don Johnson, Synchromesh fluid was developed for use in the New Venture manual transmission used by Chrysler and General Motors. Specifically, Synchromesh is formulated for transmissions that require GM Part No. 12345349 (Specification No. 9985648), GM Part No. 12345577, or Chrysler Part No. 4874464 (Specification MS-9224). Owners of Diamond Star Motors (DSM) Eclipse, Talon, and Laser cars with MMC (Mitsubishi Motor Corporation) transaxles have reported positive experiences using Synchromesh. The same can be said for owners of the Mitsubishi 3000GT and Dodge Stealth cars with the Getrag-manufactured AWD transaxles. The main benefit to DSM and 3/S owners seems to be excellent synchronizer performance, with reduced grinding and easier shifting compared to using some other gear oils.

    Pennzoil Synchromesh Fluid can be purchased as that brand or as the equivalent products: GM Synchromesh, Texaco Synchromesh, or Quaker State Synchromesh (Quaker State is part of Pennzoil). GM Synchromesh retails for about $10 per quart bottle at GM dealerships. Pennzoil Synchromesh is sold at many Auto Zone auto parts stores for about $5 per quart and should be available from Pennzoil distributors. Texaco Express Lube stores use Synchromesh but the stores I contacted would not sell the product by itself to customers. Pennzoil Synchromesh can be purchased in 5-gallon containers from

    Lubrication Basics by Don Johnson
    Noria Message Board - Synchromesh what is it?
    Pennzoil Synchromesh Fluid Product Description
    Pennzoil Technical Information P-21-C; Automotive Gear Oils
    Texaco Synchromesh Transmission Fluid
    Viscosity and Engine and Gear Oil Grades
    Last edited by NBMWSsix; 03-10-2004 at 12:58 AM.

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