What is the proper way to adjust my Hurst four speed shifter

Discussion in 'transmission and Drive train' started by grumpyvette, Mar 7, 2010.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    What is the proper way to adjust my Hurst four speed shifter?





    There is a 1/4 inch hole at the bottom of the Hurst mechanism that runs through all three levers. This is called the neutral alignment hole. To ensure proper adjustment, run the shifter from first into second and then back to neutral. Insert the neutral alignment pin (or a 1/4 inch drill bit) into the neutral alignment hole. If the 1-2 lever interferes with the smooth insertion of the alignment pin, remove the 1-2 linkage rod from the shifter and thread the adjuster button either in or out to eliminate the interference. Repeat this procedure with the 3-4 lever and reverse. To adjust the stop bolts, back the bolts out of the shifter frame until only a few threads remain. Push the stick firmly into third gear and hold. Screw in the stop bolt until contact is made. Release the stick and back the stop bolt out one turn and tighten the jamnut. Push the stick into fourth gear and repeat the procedure.
    I hope you carefully cleaned and de-greased the bolt threads and used carb cleaner spray to de-grease and flush the female threaded bolt holes in the trans and put a couple drops of loc-tite on those shifter bracket bolt threads, so it stays firmly fastened or youll eventually find that your back under the car duplicating that effort.

    http://www.chevyhiperformance.com/howto ... index.html

    Last edited by a moderator: Apr 3, 2018
  2. grumpyvette

    grumpyvette Administrator Staff Member

    Re: What is the proper way to adjust my Hurst four speed shi

    I was asked if you can fill a muncie with automatic trans fluid to make it shift smoother, the answers a huge HELL NO! a muncie trans requires a good 75w90 gear lube to function correctly, below is some related info

    REDLINE Synthetic Manual Transmission Lubricants




    http://www.modernperformanceclassics.net/ShowItem/102808 62-67 Nova Clutch Adapter Bracket.aspx


    Most manufacturers of manual transmissions and
    transaxles recommend an 80W or 90W GL-4 lubricant.
    GL-5 gears oils which are required in hypoid differentials
    are not used in most synchromesh transmissions
    because the chemicals used to provide the extreme
    pressure protection can be corrosive to synchronizers,
    which are commonly made of brass or bronze. Typically,
    the use of a GL-5 lubricant in a synchromesh
    transmission will shorten the synchronizer life by one
    half. The extreme pressure requirements of spur gears
    and helical gears found in transmissions are not nearly
    as great as found in rear-wheel drive differentials. A
    GL-4 lubricant provides adequate protection for most
    manual transmissions, unless a unique design
    consideration requires the extra protection of a GL-5.
    The reason that many manufacturers have made
    recommendations of motor oils or ATFs is that petroleum
    80W gear oils frequently do not shift well at low
    temperatures. Motor oils and ATFs are much more fluid
    at lower temperatures and they are not corrosive toward
    synchros, but they provide very poor gear protection.
    These lubricants provide almost no extreme-pressure
    protection. In addition, petroleum multigrade motor oils
    and ATFs have very poor shear stability. The shearing
    action by a manual transmission on thickeners is much
    worse than in an engine or automatic transmission.
    Within 5,000 miles the thickeners can be rendered
    ineffective and the transmission will be operating on a
    much reduced level of protection, as shown in the graph
    below. In hot weather these transmissions will whine
    and rattle because of poor vibration dampening and
    metal contact. Red Line MTL and MT-90 provide the
    excellent gear protection of a GL-4 gear oil in a synthetic
    lubricant which spans hot and cold temperatures and will
    not shear or oxidize with use.

    Red Line MTL may be used in transmissions which
    recommend 75W, 80W, or 85W GL-4 gear oils, or SAE
    30 or 5W/10W30 motor oils. If a 90W GL-4 or SAE 40,
    10W40, or 15W40 is required, MT-90 may be used. If the
    transmission or transaxle requires an SAE 90 GL-5 gear
    oil, then Red Line 75W90NS or 75W140NS Gear Oil
    may be used. In transmissions which recommend Dexron
    or Mercon fluids we recommend our D4 ATF which is
    very similar to the MTL, being a GL-4 Gear Oil also. The
    D4 ATF will provide better low-temperature shiftability,
    and the MTL would provide better wear protection for
    racing use. MTL is not designed for use in rear-wheel
    drive differentials. Those generally require a GL-5 lubricant
    such as Red Line 75W90 Gear Oil. It is not necessary
    to flush the transmission before replacing with MTL.
    Remove the drain plug and drain while warm. Seal
    compatibility has been designed to be similar to petroleum
    lubricants, and leakage should be no greater than
    any other oil of comparable viscosity. Being formulated
    with extremely stable synthetic basestocks, MTL and
    MT-90 will last much longer than conventional petroleum
    lubricants. However, we do not recommend extended
    drain intervals, since without a filtration system, there is
    no way to remove metal shavings other than draining the
    lubricant. The regular maintenance intervals are also
    recommended to insure that the proper level of the fluid
    is maintained.

    Red Line Oil's MTL and MT-90 are designed to provide excellent protection and improved shiftability for manual transmissions and transaxles, having cured the problem of hard shifting in thousands of transmissions with shifting troubles. How? They have the appropriate coefficient of friction for most manual transmission synchronizers (many gear oils, engine oils, and ATFs are too slippery for proper synchro engagement). And, the wide viscosity of MTL and MT-90 allow proper shifting over the entire temperature range which the transmission will experience. The synthetic base oils used have a very high viscosity index which provides relatively constant viscosity as temperature changes. MTL is a low 70W at very low temperatures and a high 80W, nearly an 85W, at elevated temperatures, providing adequate viscosity to prevent wear and deaden gear noise. MT-90 is a thicker 75W90 version of MTL. The shear stability and oxidation stability of these products are excellent, thus the physical characteristics of Red Line MTL and MT-90 will change little with use.


    The MT-90 is a 75W90 GL-4 Gear Oil that’s slightly heavier than MTL. Provides excellent protection of gears and synchronizers and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting.

    6100 Egret Court
    Benicia, CA 94510
    (707) 745-6100



    ================================================== ================

    Also found a place to get the STA API/GL4 gear oil. Less than $20 delivered to my door for 2 qts. Have you heard anything about this oil? Thanks, Jim

    STALUBE WEBSITE: http://www.doityourself.com/invt/6844120

    32Oz 85W90 Sta-Lube Gear Oil

    Product Description
    Gear Oil Multipurpose - Hypoid 90 Api/Gl-4 ``Sta-Lube`` Quart Bottle Weight=Sae 85W90
    Low pour points and high temperature properties to provide lubrication over a wide temperature range. Versatile, contains anti-rust and anti-wear EP additives to provide corrosion protection in drives and hypoid gears. Dark oily substance with faint petro leum odor. Plastic-safe.
    Product Details

    Price From: $5.90
    Manufacturer: Crc Industries
    Model Number: SL24229
    UPC Number: 072213242294

    ================================================== ========



    Sulfur (S) and phosphorus (P) are the primary ingredients in Extreme Pressure (EP) additives. The higher levels of EP additive in GL-5 fluids facilitate greater load and shock protection. However, controlling corrosion caused by certain reactive forms of S and P was an issue, so GL-5 oils that contained the highest levels of EP additive were not considered suitable for use in gear boxes that contained soft yellow (brass, bronze, etc.). The solution in the past was to lower the amount of EP additive (and thus, S and P) resulting in a GL-4 lube. In the last few years, more stable forms of S and P have become available and other additives have been developed that supplement the performance of lower levels of traditional EP additive. It is now possible to have a non-corrosive gear lube with GL-5 extreme pressure performance. Royal Purple Max Gear is a non-corrosive formulation (for yellow metal syncros) with extremely high load carrying capability. It is therefore suitable for use in applications (Muncie included) calling for a GL-4 or GL-5.

    So, it is perfectly safe to use Max Gear in your Muncie transmission. We also recommend it for your 12-Bolt and you do not need to add any limited-slip additive. It's already in the formulation.

    Thank you for inquiring about Royal Purple and have a great day.

    Best Regards,

    Tech Services
    Royal Purple, Inc.
    1 Royal Purple Ln.
    Porter, TX 77365
    Last edited by a moderator: Mar 11, 2019
  3. chromebumpers

    chromebumpers solid fixture here in the forum Staff Member

    OP says he does not have the Hurst shifter.
    I don’t get why the shifter wouldn’t have adjuster nuts if it was was a stock trans (according to op)
    Any early “stock” Muncie I ever seen has adjuster nuts at the shifter end of the shifter rods.
    A few words have changed but you also covered my instructions that are the same published every so often in Chevy Power mag and Hot Rod mag.
  4. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    yeah, the shifters are generally not all that difficult to adjust,
    once you understand the shifter linkage rods must not be putting any tension,
    on the transmission shiftier arms ,or the shifter ,in the neutral position,

    Standard Saginaw 3-speed transmission

    Heavy Duty full synchromesh 3-speed Borg Warner T16 delivered as the base transmission when the SS396 series was ordered.

    The special 3-speed H.D. transmission was standard on SS396 series and optional under RPO M13 in other series and the shifter was floor mounted whether a console was ordered or not.

    Gear Ratio 283 V8 and 6-cyl engines 327 and 396 V8 engines
    First 2.86:1 2.41:1
    Second 1.72:1 1.57:1
    Third 1.00:1 1.00:1
    Reverse 2.86:1 2.41:1
    Muncie 4-speed manual transmission. Note the speedometer cable exit on the passenger side. Because the speedometer cable exited on the passenger side, an extra hole was required in the firewall to accommodate the speedometer cable.


    P0221 (February 21) date stamping on 1966 Muncie 4-speed transmission.

    P7C09 (March 9) date stamping on a 1967 Muncie 4-speed transmission; (1967 was the first year to have the year stamped in the date code and the month represented by a letter code).

    [​IMG] [​IMG]
    1964 to 1968 Muncie 4-speed transmissions can be identified from later models by the way the transmission arms attach. Early Muncie side covers had a stud and the shift arm attached with a nut on the stud while the 1969 and later model side covers had a hole and the shift arms attached with a bolt.

    The Saginaw 4-speed transmission was also used and shown for "M20 PROD V-8 ENG & R.P.O. L30". Easily identified by the reverse gear being on the main case instead of the tail housing.

    Muncie 4-Speed Identification

    Casting Year(s) Ratio Ratio Ratio
    3831704 1963 Only M20 2.56 1st M21 2.20 1st
    3851325 1964 - 1965 M20 2.56 1st M21 2.20 1st
    3885010 1965 - 1967 M20 2.52 1st M21 2.20 1st M22 2.20 1st
    3925660 1968 - 1970 M20 2.52 1st M21 2.20 1st M22 2.20 1st
    3925661 1970 - 1974 M20 2.52 1st M21 2.20 1st M22 2.20 1st

    Years Type Ring(s) Ratio Reverse
    1963 - 1965 M20 None 2.56 / 1.91 / 1.48 / 1.00 3.16
    1966 - 1974 M20 Two 2.52 / 1.88 / 1.46 / 1.00 3.11
    1963 - 1974 M21 One 2.20 / 1.64 / 1.28 / 1.00 2.27
    1967 - 1974 M22 None 2.20 / 1.64 / 1.28 / 1.00 2.27

    Years Type Ring(s) Spline Input Shaft
    Tooth Count
    1963 - 1965 M20 None 10 24
    1966 - 1970 M20 Two 10 21
    1970 - 1974 M20 Two 26 21
    1963 - 1970 M21 One 10 26
    1970 - 1974 M21 One 26 26
    1967 - 1970 M22 None 10 26
    1969 - 1974 M22 None 26 26
    There are 7 different input shaft possibilities on a Muncie. All 26 spline inputs came with 32 spline output shafts and all 10 spline inputs came with 27 spline output shafts. It is commonly mistaken that all "fine spline" 26 spline input shafts are M22 transmissions. The M22 transmission has a 20 degree helix angle on the gear set as opposed to a 45 degree angle found on the M20 and M21 and were made with a higher nickel alloy. The straighter angle was designed to produce less end loading of the gear train and less heat but created more noise, thus the nickname "Rock Crusher" was born. Another misconception is if you have a drain plug you have a M22. This was only true when the first M22 boxes were created; all 3925661 castings (1970-1974) had drain plugs. The M22 was only produced in a close ratio version.

    If you are lucky and find the transmission tag (generally found on a lower bolt of the side cover), it will help identify a 1966 Muncie transmission. Unfortunately these metal tags are often discarded when repair or maintenance work is performed.

    Engine Tag Number
    RPO L34/L35 3870357 - M20
    RPO L78 3890534 - M20 (after 11/5/65)
    Optional 3879668 - M21 (prior to 11/5/65)
    Optional 3877459 - M21
    Optional 3890567 - M22 (prior to 11/4/65)
    Optional 3879993 - M22 (limited sales)
    Production V8 3884602 - 4 speed
    RPO L30 3884603 - 4 speed
    RPO L35 3890533 - M13
    RPO L34/L78 3890536 - M13


    The serial number is a date code and indicates the particular year the transmission was built for. Serial numbers from 1963 to 1966 included only the month and day. P0101 indicates January (first 01) 1st (second 01). In 1967 and 1968, the serial number got a year designator and a letter designator for the month such as P8A01, meaning 1968 (8), January (A) 1st (01). Note that a Muncie dated with a December build date it was actually built the prior year. An example would be the date code P8T13, meaning 1968 (8), December (T), 13th. The transmission was assembled December 13, 1967 for the 1968 model year. The 1969 to 1974 Muncie got a ratio designating letter at the end of the serial number. An example would be P2R25B. This decodes to 1972 (2), October (R), 25th, M21 (B).

    Date Codes: A ~ January, B ~ February, C ~ March, D ~ April, E ~ May, H ~ June
    K ~ July, M ~ August, P ~ September, R ~ October, S ~ November, T ~ December

    Type Codes: A ~ M20, B ~ M21, C ~ M22 (1969 and newer)

    Assembly Date Code Location

    Transmission Code Location
    3-speed (except Heavy Duty) Left side of main case, on boss below and to the rear of the side cover.
    3-speed (Heavy Duty) Right side of main case, just in front of extension housing.
    4-speed Right side of main case, just in front of extension housing.
    Date code example:
    Muncie 4-speed: P1025 P (Muncie), 1025 (October 25th)

    GM Standard 3-Speed Manual (L6/283) 2.85 1.68 1.00 n/a
    GM Standard 3-Speed Manual (327) 2.54 1.50 1.00 n/a
    GM H.D. 3-Speed Manual (L6/283) 2.86 1.72 1.00 n/a
    GM H.D. 3-Speed Manual (327/396) 2.41 1.57 1.00 n/a
    GM Muncie (M20) 63-65 2.56 1.91 1.48 1.00
    GM Muncie (M20) 66-74 2.52 1.88 1.46 1.00
    GM Muncie (M21/M22) 63-74 2.20 1.64 1.28 1.00

    Transmission Gear Ratio Drop Between Gears
    Standard 3-speed (L6/283) 1st to 2nd - 41.05% 2nd to 3rd - 40.48%
    Standard 3-speed (327) 1st to 2nd - 40.95% 2nd to 3rd - 36.71%
    H.D. 3-speed (L6/283) 1st to 2nd - 39.87% 2nd to 3rd - 41.87%
    H.D. 3-speed (327/396) 1st to 2nd - 34.85% 2nd to 3rd - 36.31%
    M20 (early) 1st to 2nd - 25.39% 2nd to 3rd - 22.51% 3rd to 4th - 32.43%
    M20 (late) 1st to 2nd - 25.39% 2nd to 3rd - 22.34% 3rd to 4th - 31.51%
    M21/M22 1st to 2nd - 25.45% 2nd to 3rd - 21.95% 3rd to 4th - 21.88%
    Manual transmission part numbers

    Part Number Reference Fitment
    3901103 AIM - M20/A1 RPO M20 with production V-8 engine
    3901104 AIM - M20/A1 RPO M20 - Optional
    3890533 AIM - M20/A1 RPO M20 with RPO L30 327/275hp engine
    3870357 AIM - M20/A1 RPO M20 13817-867 & RPO L35 396/325hp engine
    3879668 * AIM - M20/A1 RPO M21
    3879993 AIM - M20/A1 RPO M22
    3873892 AIM - M10/A3 RPO M10 3-speed with overdrive
    * 3879668 was 3877459 - revised in 1967 but date unreadable

    Muncie 4-Speed Casting Numbers

    Main Case
    3831704 1963 Only small 6207NR Front Bearing ,Pat. Pending, 7/8" Bore
    3839606 1963 - 1964 Regular Bearing Pat. Pending, 7/8" Bore
    3864_____ 1964 Milled off last 3 digits 7/8" Bore Patent Pending
    3851325 1964 -1965 7/8" Bore Patent Pending Mostly 1964
    3851325 1964 –1965 7/8" Bore Patent Number
    3885010 1966 -1967 1" Bore Patent Number
    3925660 1968 – 1970 1" Bore Patent Number
    3925661 1970 – 1974 (some early 1975 cars) 1" Bore Patent Number
    Tail Housing

    3831731 1963 "Thin Fin Tail" Driver speedometer 27 spline
    3846429 1963 "Thin Fin Tail" Driver speedometer 27 spline
    3846429 1963-1965 Regular thick web, driver speedometer, 27 spline
    9779246 1964 – 1965 Pontiac Catalina Long Tail Driver Speedo 27 Spline
    3857584 1966 – 1970 Passenger side speedometer, 27 spline
    3978764 1970 – 1974 passenger speedometer, 32 spline output
    Side Cover

    3831707 1963-1965 Early side cover stud type shift shafts
    3884685 Cover issued with "584" tail stud type shift shafts
    3950306 Short boss with bolt on type shift shafts - no switches
    3952642 Long boss bolt on type w/ TCS switch on 3-4
    3952648 Short boss bolt on type w/ TCS switch on 3-4
    335308 Long boss bolt on type with neutral safety switch. Some have a boss for the switch that is cast but not machined on 1-2.
    Last edited: Mar 11, 2019
  5. chromebumpers

    chromebumpers solid fixture here in the forum Staff Member

    I wonder how many people know about the simple rod placement to the second hole on the Muncie shifting lever to shorten the 2 - 3 shift gate “H” zig zag? I have return to edit this photo to insert pointers - as soon as I can figure out how to do it.

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