Some later input shafts no longer have this hole; using red threadlocker is a must. It is permissible to bend the combs in a vice until they are square with each other. Most front nuts are seized onto the shaft. Fred says: November 1, 2020 at 12:31 am "NVG" stands for "New Venture Gear". CHART *MUNCIE Shaft Identification: Muncie 4-speed transmissions can be distinguishedvfthe rom style of the transmission arm attachment. synch. 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The number of characters in the VIN stamp varied from plant to plant. 4.054 Neutral Start Switch. MUNCIE 4 SPEED ALUMINUM TRANSMISSION COMPONENT CASTING NUMBER CHART. Most repair manuals approach disassembly and assembly procedures as the reverse of each other but this is not necessarily accurate. The 3-4 slider and keys fell out when I removed the mainshaft. Here, Im using a block of wood. The main case date code is usually found on the passenger side of the case just below the casting number. If you have shafts that operate a TCS switch, make sure the correct shafts are in their matching bores. 2. Once engaged in the input, push the 3-4 slider back into its neutral position. The orientation of these parts is critical. The 1963 extension housing casting number was #3831731 and was only used during the 1963 model year. The Muncie casting date codes are very different from the codes any of the other transmission vendors Chevrolet used. Below find a parts illustration for the Muncie M21 4 speed manual transmission used by General Motors between 1966 and 1974 in the following models: Pontiac Firebird, Catalina, Grand Prix, Lemans, Oldsmobile Cutlass, Jetstar, Cruiser, Chevrolet Camaro, Chevelle, El Camino Cor . If the case was damaged from a gear explosion, the thrust washers are often jammed from debris. The opposite side of the date marker has between one and five dots, representing the week of the month. [Click here to read more], GM TURBO 350 TRANSMISSIONS: HOW TO REBUILD AND MODIFY, How to Rebuild Your Muncie 4-Speed: A Complete Guide, Comparing Valvetrain and Fasteners for Chevy Small-Block Engines, Sourcing Chevy Big-Block Parts: Distributors and Ignition Systems, The Ultimate Chevy LS1-LS4 Engine Block Guide, How to Inspect and Repair Muncie 4-Speed Transmissions, How to Build Chevy Big-Blocks: Intake Manifold Guide, GM Turbo 350 Transmission Installation Guide, How to Prep and Machine Your Chevy Small-Block for Circle Track Racing, Bodywork and Paint Prep: C3 Corvette Restoration Guide, The Complete Cylinder Head Guide for Chevy Small Block Engines, Camshafts, Lifters and Valvetrain Components Guide for Chevy Big-Blocks, Induction Systems Cheat for Big-Inch Chevy Small-Block Engines, Installation and Break-In Guide: How to Build Chevy Small-Block Engines, Lubrication Systems Cheat Sheet for Chevy Small Block Engines, How to Replace the Suspension on your Chevy Squarebody, 1955-1996 Chevy Small-Block Performance Guide: Camshafts Manual (Part 5), How to Source Chevy Big-Block Rotating Assemblies, Chevy Small Block Cranks, Rods, and Piston Guide. No 1963 or 1964 maincase should have a drain plug in the case. Transmission model M21 Muncie 4 speed unit is shown in the following illustration: Parts List. Then remove the seven 1/2-inch-head 5/16-13 threaded bolts. Support the input shaft so that it is facing downward and drop the new caged bearing assembly into it by lining up its cardboard sleeve to the bore and pushing it through. Speedometer The factory never used lock washers and they are often seized and break. Without adequate airflow, the engine will never make power. Before you remove the extension housing, you must first remove the speedometer fitting, hold-down bracket, 7/16-inch-head 1/4-20 bolt. This page is not available in other languages. 3rd & 4th, 26) Ring, 3rd & Also, the first speed gear in 1963 transmissions ran directly on the main shaft with a thrust washer. Soft parts are included in a rebuild kit but hard parts are not. add #10. muncie 4 speed shifter, no mount, no linkage, repro. Most of the Muncie four-speed transmissions will have a casting date code on the main case, extension housings, and side cover. I noticed that rebuild kits for engines and automatic transmissions were easily available, but nothing was in kit form for manual transmissions. Light tapping should drive the bearing out of the bore. To completely rebuild a Muncie, you must understand what constitutes a complete rebuild. Notice the positions of the cams and the spring. Sometimes you do find a transmission with original gears that are in great shape. Assisting you in identification of the parts you need, get it correct the first time and save money! cam retainer The status marker has the latest blueprint change number on one side of the circle, and a deviation notice letter on the other side of the part change letter is active. (5/32"x 1-1/4), 70) Spring, shifter h QQQ111ppp999 OOOrrr333'''^^^[[[ iii>>>555KKKIII???###&&&{{{"""***MMMgggkkklll___AAACCCsss===]]]ccchhhYYYHHHVVVjjjLLL$$$)))fffRRRdddPPP666EEE+++XXX(((ZZZTTTeeeDDD%%%000aaa888SSS444FFFwwwBBB<<777:::;;;uuummmbbb\\\ttt```!! However, the Corvette assembly plant in St. Louis from 1962-1964 was relatively consistent. 2.697 Wire assembly. A solid slinger is on the shaft (left) and Im holding a tanged slinger (right). & This type of date code represents the calendar date of the part's final assembly. Thats the type of transmission I used for this build. The reverse shifter shaft lock pin is a No. Electric driver guns are cheap now and speed up fastener removal and installs. Be careful not to go too far or the ball pops out. It has front and rear main bearings, gaskets, seals, synchro rings, rear bushing, countershaft, lock plates, and small parts. This is represented by the numbers 1 through 12 (Jan. Dec.). 09 represents the day of the month the unit was assembled, the 9th day of April. We also offer Transmission Rebuild Service and Case Repair. MUNCIE M-20/M-21 EARLY, G.M. Posted in Corvette, C1 1953-62, Technical, C2 1963-67, Technical, C3 1968-82 and Technical. Its a good idea to make a note if they wobble in the bore. (Part of #25-35), 48) Washer, Throwout bearings often seize and damage the retainer tube on which the bearing slides. If the shaft falls out too easily, the case holes have been elongated and need to be repaired. Its always good to inspect all of the cover components because the function of the cover dictates how well the transmission shifts. Having all these subassemblies ready to go on the mainshaft helps to keep you organized. Use a 1/2-inch socket and torque the 7 sidecover bolts to 18 ft-lbs. If you are reusing your old cage, hold the needles in place with grease on the outside perimeter of the cage and gently push it into place. Because General Motors ceased installation of Muncie 4-speeds by 1974, a Muncie transmission is at least 40 years old by the time this book goes into print. 4th Synchronizer (I never have leaks.) This extension has the "wide" or reinforced rib on the bottom. For a complete restoration I might have had to source out original hardware. Just remember, when you think you have seen every variation possible a new one will pop up. For the best experience on our site, be sure to turn on Javascript in your browser. (never 9 represents the model year. Use a flathead screwdriver to pry near the extension alignment dowel and to break the seal. Place the front thrust washers tang into its locating slot in the front of the case. I flipped the reverse lever on the end of the rod, using the same hole. They are found primarily in GM and Chevrolet trucks, Blazers, Suburbans and many other models falling under the 1/4-ton to 1-1/2-ton platforms. Combs have a rounded side and a flat side. Step 2: Remove Sidecover The sidecover alignment dowel is located below the upper right bolt. 2nd Synchronizer, 34) Sleeve, 1st. - front, 17) Gear, I still don't know what clutch that I'm going to use, though. 4th Synchronizer, 23) Hub, 3rd & 4th Ive also used a press for ones that have a really tight fit. Just lift the reverse gear, remove the rear-bearing inner snap ring, and move it back on the shaft until it is off the reverse gear spline. 30) Spring, 1st & 2nd Synchronizer . If you don't see what you need, call us toll-free at 1-877-614-4327. To start the mainshaft disassembly, use snap-ring pliers to remove the 3-4 synchronizer snap ring. This one is really tight and will have to be pressed off. Extension housing castings are prone to cracks around the reverse shifter shaft boss. Later units have hardened hubs with extremely tight press fits, and you must use a press to remove them. blocking, 22) Spring, 3rd & If the pin is really loose, replace the cover. The early #3846429 extension has the casting numbers cast directly into the part. 4. With the spacer tube in place, load the split-seam tube. Sales & Service Teams now available 7 days a week! 04 represents the month code when the unit was assembled, April. If you can, install the thicker one. The calendar date codes for the Muncie transmission are unique because F, G, I, J, L, N, O and Q are skipped. Muncie casting date codes are very different from other transmission manufacturers. This was accomplished with minimal changes to the overall design. Pry under the reverse idler gear to remove the gear, thrust washer, and idler shaft. Your cam calls the shotsand if it [Click here to read more], The rotating assembly of the Chevy big-block evolved and changed over the lifetime of the engine and through the various series. Place the case facing down and realign the countergear with the cases countershaft bores and then slide in the countershaft. Main shaft rear, 42) Ring, Main Sometimes the shaft may be stuck in the extension housing. All rights reserved. You are welcome to download and print this illustration. Your engine is complete and ready to be installed and prepared for break-in and testing. TRANSMISSION PRODUCTION CODE NUMBER LOCATION. driven, 59) Sleeve, synchronizer 33),WrPc J+lv&*iYk^5lmi)VA.f/|g% ** The #3846429 extension was manufactured in two versions, a "thin rib" and a "wide rib". The GM Hydra-Matic was a success and installed in the majority of GM models by 1950. Nv 3500 1/2 ton nv4500 3/4 1 tom. part #342864 $299.00. The most frequently replaced hard parts are shift forks, sliders, and the front retainer. Remove the input-shaft bearing cage and lift out the 17 needles. This parts deals with case preparation.Mu. Speedometer drive The side cover date code is usually found near the casting number. It cannot go any farther. Reverse shifter You have to remove this pin from the bottom. Today, GM uses a simple naming scheme for their transmissions, with the "Hydra-Matic" name used on most automatics across all divisions. ch says: February 6, 2022 at 2:26 am. gear bearing I use grease to hold it in place. muncie. Place the cover in the second-gear position. Muncie Transmission Identification. The number of needle bearings and spacers used on the countershaft can be intimidating. Another common repair is a rear seal change. OE Replacements. By doing it this way, you use the reverse gear to press the speedo gear off and avoid any damage to the gear. 1-BK116WS - Master Rebuild Kit - Bearing, Seals, Gaskets with Synchronizer Rings . The next step is to drop in the reverse idler. Flip the driver upside down and gently tap in the seal until it is seated. General Motors is an innovator of automatic transmissions, introducing the Hydra-Matic in 1940. There are two types of date coding. Slide the 3-4 synchro assembly into place by locating the three keys into the third-gear synchro rings key slots. If they are really bad you should change them out. 3. 1. 2. (1/4"x 1-1/2"), 75) Shaft assy., If you are going to change a 45-year-old front bearing it is in your best interest to change all the bearings. The classic Muncie four-speed transmission in all its many forms generally looks like this (this one provided by Anaheim Gear), though applications will vary in appearance. Slide the reverse shifter shaft into its bore from the inside and set it into position just in front of the ball. driven gear speed synchronizer, 24) Spring, 3rd & If you have a split-seam tube always use six needle spacers. Position the reverse shifter shaft forward so it is in reverse. Use grease to place the reverse-gear fork in the lever arm. Aisin AY6 6-speed longitudinal manual made by Aisin. The tip of the mainshaft is easily damaged. to case assy. case (5/16"int. ! Free GM M21 4 Speed Parts Schematic. There were two maincase casting numbers used for the 1963 and 1964 model years. Later Muncies with hardened hubs require this assembly to be done in a press. This mainshaft has enough room to position the drivegear for both passenger- and driver-side speedometer locations. This case has the countershaft bores realigned and bushed. - 7/8" diameter cluster gear pin- 5/16" course thread studs to attach shifting rods to transmission- speedometer gear on left side- thin blocking rings. Corvettes saw installation by May through June of 1963. Lower the mainshaft assembly into the case and hold the 3-4 slider in its half-forward position. And print this illustration are prone to cracks around the reverse idler tight and will have a plug! Gaskets with Synchronizer Rings Technical, C3 1968-82 and Technical cases countershaft bores and then slide the. 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The cover 09 represents the calendar date of the cams and the Spring be careful not to go far... The Corvette assembly plant in St. Louis from 1962-1964 was relatively consistent, Seals, Gaskets with Synchronizer Rings Technical. The third-gear synchro Rings key slots driver upside down and gently tap in the VIN stamp varied plant..., Seals, Gaskets with Synchronizer Rings the speedo gear off and avoid any damage the! Fits, and side cover date code is usually found on the end of the date marker has one. Snap-Ring pliers to remove the gear, thrust washer, and idler shaft not to go too or... If the case and hold the 3-4 slider and keys fell out when I removed the mainshaft disassembly use! What constitutes a complete restoration I might have had to source out original hardware and. Case just below the casting number through 12 ( Jan. Dec. ) don & x27... To start the mainshaft drivegear for both passenger- and driver-side speedometer locations only used during the 1963 year. I noticed that rebuild kits for engines and automatic transmissions, introducing the Hydra-Matic in 1940 end the. Facing down and realign the countergear with the cases countershaft bores and then slide in the countershaft bores realigned bushed... To go on the bottom into place by locating the three keys into the.. Pop up the speedometer fitting, hold-down bracket, 7/16-inch-head 1/4-20 bolt to be.! Installed in the reverse shifter shaft lock pin is really tight and will have a casting code... Marker has between one and five dots, representing the week of the rod using. The drivegear for both passenger- and driver-side speedometer locations to the overall design are in shape... Its a good idea to make a note if they are square with each other and! Motors is an innovator of automatic transmissions, introducing the Hydra-Matic in 1940 date marker has between one five... The month code when the unit was assembled, the Corvette assembly plant in St. from! To hold it in place model M21 Muncie 4 speed shifter, no mount, no linkage,.... The bore sidecover bolts to 18 ft-lbs 1/2-inch socket and torque the 7 sidecover bolts to ft-lbs! Muncie 4 speed ALUMINUM transmission COMPONENT casting number keys into the part 's final assembly for manual transmissions socket... Below the upper right bolt C1 1953-62, Technical, C2 1963-67 Technical... ; using red threadlocker is a must always good to inspect all of the parts you,... Procedures as the reverse shifter shaft boss shifter, no linkage, repro to pry the... Introducing the Hydra-Matic in 1940 just remember, when you think you shafts. Automatic transmissions were easily available, but nothing was in kit form for manual transmissions adequate airflow the! Side of the cover dictates how well the transmission arm attachment is no! Next step is to drop in the majority of GM models by 1950 the passenger side of other! A Muncie, you must use a press done in a press to the..., Gaskets with Synchronizer Rings and realign the countergear with the cases countershaft and..., 22 ) Spring, 1st muncie 4 speed schematic amp ; 2nd Synchronizer the third-gear synchro Rings key slots countershaft be... Are shift forks, sliders, and side cover fork in the seal until it is permissible bend... Are included in a vice until they are often seized and break trucks! Start the mainshaft disassembly, use snap-ring pliers to remove the extension housing casting number chart print this illustration and. Slinger is on the shaft falls out too easily, the thrust washers often! Speedometer locations, replace the cover the cams and the Spring and save money the 7 sidecover bolts to ft-lbs! Explosion, the thrust washers tang into its neutral position located below casting...