Drive in the shaft until the lower stepped portion of the shaft is horizontal and flush with the rear of the case. 1969-1974 production codes may contain an additional letter, for example: P9D09A. Corvettes saw installation by May through June of 1963. In Argentina, the Turbo Hydra-Matic was available on some models of the 1969-1978 Chevrolet "Chevy," essentially the 1968 U.S. Nova, but was marketed as the "Chevromatic.". MUNCIE M-20/M-21 EARLY, G.M. Chevrolet needed a way to track engineering and production changes relative to model usage and the date coding of a particular part allowed changes to be documented and recorded. Some have one that is .015-inch and the other is .030-inch thick. 0 Once I feel both the fork and gear are connected, I drop the tailhousing onto the midplate. It cuts a nice slot in the bushing when you hit it with a hammer. Its much easier to place the reverse shifter shaft seal in the tailhousing after the shaft is in place. Main shaft rear, 42) Ring, Main The helical, square spline design causes a sloppy fit between the gear and mainshaft. Notice the positions of the cams and the spring. This is an easy repair because failure of the retainer is not caused by something internal. Last time we talked about how to distinguish a Muncie four-speed transmission. cF You can use an exhaust pipe separator chisel and small chisel to remove the extension housing bushing and rear seal. I apply red threadlocker to the threads on the input shaft and stake the nut with a punch over the air-bleed hole of the input. The Muncie transmission was an aluminum main case/extension housing, side-loaded transmission with a side-lever shift linkage. The system, or type of workflow, I have developed allows me to ship transmissions worldwide without any issues or comebacks. For a complete restoration I might have had to source out original hardware. Apply assembly lube to the shifter shafts and install them in the cover. Flip the driver upside down and gently tap in the seal until it is seated. Muncie 1965-72 1965-68 Pontiac 1966-72 "A" . Once clamped, the 51813 Permatex sets up within 15 minutes. synchronizer The first type of date coding can be found on parts that are comprised of several smaller components, such as alternators, distributors, etc. Shifter lever to 2. This code will be stamped onto the main case. OE Replacements. These grooves were cut into the input shaft so the Muncie assembly line worker could easily identify which input shaft should be installed in a particular unit. I always replace these with a 20-pound cover spring. The only special tool you need is a Muncie front-nut wrench (the red one here). Small parts kits usually have three selective-fit rear snap rings. If it is a used part, make sure that the idler has no up-and-down play on the shaft. If you have shafts that operate a TCS switch, make sure the correct shafts are in their matching bores. Because several different replacement front bearing retainers are available, different-thickness gaskets are necessary. Seal removal tools are available and worth having if you build a lot of transmissions. Install the second-speed gear with the synchro ring and the 1-2 synchro assembly. If they do wobble, the seals wear out prematurely because bores in the cover are also worn. I tracked down the original OEM parts that I thought would make a great kit and started selling them to the public at car shows. The Muncie was used in all high performance applications until the Borg-Warner Second Design Super T-10 began replacing it in 1974. The late 1964 extension housing casting number was also #3846429 and was used through February of 1965. I usually take off the sidecover to see if the gearset has been run low on oil, has some broken teeth, or worn sliders and shift forks. Once you remove the shaft you get a great view of the packed needles. Some sets have two .015-inch gaskets that can be stacked. 2nd Speed, 29) Ring, 3rd & The object is to get the thickest ring in the rear mainshaft snap-ring groove. (451) 7 bolt side cover used from 1963-68 * MUNCIE Shaft Identification The above Muncie 4 speed transmissions can be distinguished from the style of the transmission arm attachment. 1956-1964 4 speed Controlled coupling HydraMatic, also known as Cadillac 315 or P 315 HydraMatic, Oldsmobile Jetaway, Pontiac Super HydraMatic. These seals seat in the bore with light taps. Make sure it clears the front thrust washer and seats in the front bore. Without adequate airflow, the engine will never make power. 2nd Synchronizer, 31) Hub, 1st &2nd Then remove the seven 1/2-inch-head 5/16-13 threaded bolts. The calendar date codes for the Muncie transmission are unique because F, G, I, J, L, N, O and Q are skipped. 1st, 2nd, 3rd, 4th, 78) Belt, Cover to (I never have leaks.) 1. GM Muncie SM420 Transmission. Buy factory direct, let us help you save some money! \;1"89ek5YAwG Rv($|)d 40312 County 8 Blvd, Zumbrota, MN 559928 am - 5 pm CST507-824-2012, Toll Free Phone: 1-888-824-2012info@midwesttrans.com, 11071 93rd Ave N Maple Grove, MN 553698 am - 5 pm CST763-425-7474Toll Free Phone: 1-800-444-0755info@midwesttrans.com, Contact Us | FAQ | Warranty | Privacy Policy | Terms & Conditions, Automotive Repair Shop Website Design by One Wheel Marketing. The first documented Corvettes with the Muncie transmission appear in the May-June time frame. There is another way to quickly identify Muncie transmissions. Always check to see that the date marked precedes the final assembly stamp code. Position the 3-4 slider forward (about halfway) on the hub but not far enough to displace the strut keys. The sealant on the cover gaskets also acts as a threadlocker. All of the casting codes should be within 30 to 90 days of each other and in most cases will be reasonably close to each other. 2.698 Backup Light Switch Brackets. P represents the manufacturing plant, Muncie. Electric driver guns are cheap now and speed up fastener removal and installs. (5/16"). This one tapped gently into place. There are two types of date coding. Muncie 4 Speed Bearing Retainers Complete Muncie Transmission Units You are welcome to download and print this illustration. P represents the manufacturing plant, Muncie. Tap down the midplate with a punch, but if you feel its on the tight side use a press, supporting it by the rear bearing inner race. 2.697 Wire assembly. Always reinstall the spring facing in this direction. lever to shaft Place the transmission back on your bench with something to support the extension housing. I want the load to be even around the whole circumference of the tailhousing. retainer to case Throwout bearings often seize and damage the retainer tube on which the bearing slides. Transmission 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. Click the button below and we will send you an exclusive deal on this book. According to an official report by the SAE (Society of Automotive Engineers) the design of the 10-speed gearbox is essentially all Ford, while GM was responsible for designing the 9-speed 9T transverse automatic gearbox. The second type of date code, which is the most common, refers to the casting date code. With the spacer tube in place, load the split-seam tube. endstream endobj 3 0 obj <>stream With this method, place the bearing and shaft back into the case and install the outer snap ring on the bearing. Simply lift the forward reverse idler and thrust washer from the case. Aisin AY6 6-speed longitudinal manual made by Aisin. The last detail is to install the speedometer fitting and speedometer gear. - 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. I coat the outer edges of the sidecover seal with Permatex 51813. The SM420 is an impressive, heavy-duty truck transmission designed for and used in , 3/4, 1 and 2 ton trucks. The combs must be flat. h QQQ111ppp999 OOOrrr333'''^^^[[[ iii>>>555KKKIII???###&&&{{{"""***MMMgggkkklll___AAACCCsss===]]]ccchhhYYYHHHVVVjjjLLL$$$)))fffRRRdddPPP666EEE+++XXX(((ZZZTTTeeeDDD%%%000aaa888SSS444FFFwwwBBB<<777:::;;;uuummmbbb\\\ttt```!! Filed Under: Chevy Tech Tips, Transmissions, Power adders have been used since the earliest days of the automotive industry, and they continue to be a popular method for boosting engine performance cost effectively and reliably. This case has the countershaft bores realigned and bushed. At first I had alignment issues with the reverse lever and rod. For the best experience on our site, be sure to turn on Javascript in your browser. 1967-1974 production codes will start with the letter P and have five numbers, for example: P9D09. reverse sliding, 40) Bearing assy., Most passenger car plants stamped the VIN on the top, while other plants stamped it on the side, near the assembly date code. R@W4a'K/n$ ~%JnH0('$uHQ2yh? A solid slinger is on the shaft (left) and Im holding a tanged slinger (right). If the transmission goes together with the sliders installed incorrectly, the worst thing that happens is that when you go to fit the sidecover on (the last step), nothing fits. The Turbo-Hydramatic was used by all GM divisions, and formed the basis for the company's modern Hydramatic line. Grease does two things: It keeps the seal lubricated and it also keeps the seals tension spring from popping out when you drive the seal in. This code was used until 1967 when the code was changed to include the model year. One half of the Date Marker circle will have a month designator for when the part was cast. The 1965 Muncie was identical to the 1964 version. If that has happened, stand the case on its front face, so the loose gear doesnt cock or move off center, and rotate it as you remove it. Use this method on every gasket surface on the transmission. 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. Remove both shift levers and mark them so they can be replaced in the same bores. shifting Position the 1-2 slider forward in second gear, and shift the sidecover 1-2 fork into second. 5ET50 (MKV) - Electronically controlled, continuously variable automatic transaxle (Second Generation Chevrolet Volt). Speedometer drive You never want to hammer hard on this sleeve because you can spread the end and cause first gear to bind on it. bearing retainer Install first gear with a little oil in its bore. Turn the mainshaft so that the 3-4 strut keys drop into their matching slots on the fourth-gear synchro ring. Thats the type of transmission I used for this build. Before fully seating the midplate make sure that the midplates dowel is aligned with the main case and the 3-4 struts are in the key slots of both the third and fourth synchro rings. I spend most of my time building new transmissions with all-new parts. *1sQawB5BNxenlVyM0*3R ,&#]Djmyp (The M does not stand for "Muncie.") Typically, when you ordered a GM car you had standard options and accessories installed. Well, there you have it. You do not need to change the split roll pin in the reverse idler shaft unless its loose or you are replacing it with a new shaft. Grease the rear seal and coat the outside of the seal with Permatex 51813. TempestTorque, ( Pontiac) a two speed based on Powerglide, but having the added feature of " Split Torque " dividing the engine power between mechanical connection and the torque converter in high gear. Pry near the dowel to remove the cover. You need to be in second gear to clear the reverse idler case boss. (5/16"-18x3/4"), 79) Washer, synch. The most frequently replaced hard parts are shift forks, sliders, and the front retainer. The location of the VIN stamp can vary but it can usually be found on the top leading edge of the main case or on a mounting surface near the Build Date Code. You can place the case subassembly facing down on an old case or bellhousing. Quality parts guaranteed! Never strike the input shaft itself. In-exchange for Ford's 10-speed transmission, General Motors will let Ford use its 9-speed transmission for front-wheel drive applications; Ford ultimately declined use of the 9T and instead, removed 1 gear and used the 9T as an 8-speed transmission.[2][3][4]. q )A :l 4}3vNSK{^ %cD;&OJ! Because youre taking apart the entire suspension, it makes sense to do this at a place where the truck can sit for a minimum of a [Click here to read more], Selecting a camshaft is one of the most important decisions youll face when building a high-performance small-block for street or bracket racing. Steel gears should always replace the plastic gears. On the main cases, the code is usually found on the passenger side of the case, below the casting number. I noticed that rebuild kits for engines and automatic transmissions were easily available, but nothing was in kit form for manual transmissions. Transmission Be careful not to go too far or the ball pops out. A third variant was the light-duty rear wheel drive Turbo-Hydramatic 180 used in many European models. One circle is called the date marker, the other the status marker. Use a 9/16 socket and torque the four bolts to 25 ft-lbs. Most repair manuals approach disassembly and assembly procedures as the reverse of each other but this is not necessarily accurate. Put the reverse tapered pin in after you check for binding, and make sure everything spins smoothly. This type of date code represents the calendar date of when the part was manufactured. It is permissible to bend the combs in a vice until they are square with each other. transmission Case Use pliers or a spring hook to install the spring. Place a new locating snap ring in the midplate, spread it open, and start the rear bearing in the bore. Some first-gear bushings drop down easily and you may need a little threadlocker on the sleeve to prevent it from spinning on the shaft. You can copy and paste this link to share: https://www.chevydiy.com/how-to-rebuild-your-muncie-4-speed-a-complete-guide/. I use a pry bar to press the ball down as I put pressure on the lever to move it on top of the ball. People also have used a punch to remove and install them and this method also damages the gears. Countershaft locating, 16) Gasket, Rear hSmk0+}f[2B`lA3 endstream endobj startxref In this diagram from the service manual, heavy bearing grease is used to retain 17 new roller bearings and a retaining cage into the main drive gear cavity before installing the unit . I always grind a 45-degree chamfer into the front of the forward reverse-idler teeth because some sliders hit them when in first gear. The lower part of the Status Marker circle will contain a letter to note any deviations notice. 2. You should be able to drive the countershaft from the case with moderate effort. 4th synchronizer, 21) Ring, 3rd & 4th Slide the reverse shifter shaft into its bore from the inside and set it into position just in front of the ball. If you liked this article you will LOVE the full book. You need to have the transmission locked in two gears so you can install the new maindrive nut. 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. The following vehicles are likely sources of a Muncie four-speed. assy., Transmission (Part of #25-35), 48) Washer, 4. The 1964 Muncie transmission was a basic carryover of the 1963 transmission with the exception of the 1964 and later gearboxes used a first gear sleeve on the main shaft for better lubrication. Make sure the seal is square in the bore and that you drive it in evenly. bearing, 8) Bolt, Bearing It is documented that from 196264, Corvettes did not use an assembly plant designation for the first digit. clutch, 18) Bearing assy., Some speedometer drivegears on 1969 and 1970 transmissions are plastic and are held on with a clip. You will disassemble it later. I use solid oil slingers and not the ones with four tangs, which tend to break off. The 1963 extension housing casting number was #3831731 and was only used during the 1963 model year. If you are going to change a 45-year-old front bearing it is in your best interest to change all the bearings. *This transmission is part of a joint-venture between General Motors and Ford Motor Company to split development of two transmissions, a longitudinal 10-speed and transverse 9-speed. hXyp%X xu=|un/f)Tzj f5]6%&x7RucO,Mm!W#GSMtnT{zLXTTGq))- Characteristics of the VIN stamp, including the location of the pad, the type size of the stamp, and the stamping method (gang or individual), was chosen by the final assembly plant. No 1963 or 1964 maincase should have a drain plug in the case. Removal of the front bearing cover is where disassembly begins. shaft Use your hand to apply upward pressure to the countergear so you take the load off the countershaft. View M20 M21 M22 Muncie-4-Speed Transmission Diagram / Drawing / Exploded View / Parts Breakdown. blocking, 27) Gear, Put your other hand over the C-clip to catch it once it clears the cam. I pre-position the bolts in the lock plates and apply sealant to them. There was only one side cover casting number used during the 1963 and 1964 model year. You will note that to shoot this video, I had to bench assemble the transmission and the shifter with the crossmember for in order to show the complete support geometry:The transmission is bolted to the crossmember.The shifter mounting bracket is bolted to the crossmember.The shifter is braced to diagonally to the crossmember on the driver's side.The shifter is braced to the transmission with a rubber cushioned arm.The shifter's throw arms in 2nd and 4th have very little clearance with the crossmember. Shifter lever to zzzxxx}}}vvv~~~qqq F7~ New needles are in small parts and rebuild kits, but the cages are not. The sidecover alignment dowel is located below the upper right bolt. Synchronizer, 35) Synchronizer If you don't see what you need, call us toll-free at 1-877-614-4327. Once its together, I trial fit it by installing the input shaft and front bearing from the inside of the case. gear sleeve oil, 66) Nut, Shifter It was based on the T10 design, and I have been told that BorgWarner engineers helped design it. Once the ring is seated fully in place, slide the reverse gear onto the mainshaft. Press the mainshaft through the complete assembly all in one shot. add #12. shifter boot retainer & bezel plate ,manual new 67 68 camaro 68-73 nova . bearing, 6) Spacer, (never Once engaged in the input, push the 3-4 slider back into its neutral position. speed synchronizer, 24) Spring, 3rd & 1963 & 1964 Muncie Transmission: Passenger and Corvette models stamped on the left side of case rear of side cover. On the other hand, St. Louis-built passenger cars had the letter "S" as the first digit. The 1964 maincase casting number was #3851325 and was used through the 1965 model year as well. 1963-1964 production codes will be stamped on the right side of the main case. 1965-1974 production codes will be stamped on the right side of the main case, just ahead of the tailhousing on the vertical boss pad of the case. Catch the rear idlers splines on the internal splines of the forward idler. Soft parts are included in a rebuild kit but hard parts are not. Ive also used a press for ones that have a really tight fit. Also, the 1963 Muncie tail housing had a single thin casting rib that ran along the bottom of the tail housing. After all the gaskets have been removed, clean up the gasket surfaces using a file. NOTE: We have included the 1966-74 Muncie identification above for reference usage only. If you have an odd code on any component send me a high-resolution photo, I am always learning and appreciate the unusual. The stamping method used could be "gang" or 'individual" stamped, this method varied and was chosen by the assembly plant. ball, 71) Ball, Reverse D represents the month code when the unit was assembled, April. All original Muncie transmissions have identification ring grooves on the input shaft. fits all muncie m20, m21, & m22 models; includes gaskets, & seals; also includes smaller bearing retainer gasket for some very early units with smaller retainer; The 1963 maincase casting number was #3831704. The next-generation transmissions, introduced in the early 1990s, were the electronic Hydra-Matics based on the Turbo-Hydramatic design. Grinding tends to create burrs on the gears so I use a bench grinder and then clean up the edges with a flexible shaft. 1963-1966 production codes will start with the letter P and have four numbers, for example: P0421. Once I fully chamfer and deburr the gear, I install the forward reverse-idler thrust washer and hold it in place with grease. Shifter lever to Another common repair is a rear seal change. part #342864 $299.00. I flipped the reverse lever on the end of the rod, using the same hole. All Muncie 4-speed transmissions were stamped at the Muncie assembly plant with a production code number, consisting of a prefix letter, production date and shift suffix letter where day and night shifts were in operation. Countershaft I typically replace the forks because most are worn, and they are just too old. assy., Transmission I like to use lock washers even though the factory never used them. The Muncie has probably been the most popular transmission among the hot rodding set since its inception in 1963. Some mainshafts have circular grooves cut into the reverse gear spline for these tiny anti-rattle springs. It remains tacky even when the air temperature is high. blocking, 30) Spring, 1st & hT1O0ol\|:#10P,t45 u"@o]Ive"3-BCU_DWJMU^%{_B$F#UBK+%X.:5ss:azvc88,5n(.K}' _)qYeb-UP7 I Muncie 4-Speed . It is the successor to the old "New Process" gear company. In this case, youre loading 112 needle bearings. I always install the combs in the cover with the flat sides facing each other and then I attach the E-Clip to make sure it is fully seated in the pins groove. So any recommendations on LS style . 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. The most common small repair is to change the front bearing retainer. A dummy shaft is a slightly smaller shaft that is positioned in the gear and needles and spacers are loaded around it. Trans. Free GM M21 4 Speed Parts Schematic. This extension has the "wide" or reinforced rib on the bottom. l)3:9(kW7x M,]Ff2 If you are reusing a case with a stock bore, use 51813 Permatex to coat the front bore and rear of the shaft. Log in to add vehicles or quickly search your stored vehicles. If you plan to reuse them, you should remove the gear over a tray so you avoid losing any needle bearings. From the left, the subassemblies are the tail section, main case, sidecover, and mainshaft with midplate. To completely rebuild a Muncie, you must understand what constitutes a complete rebuild. Apply as much lube as necessary to hold the needles in place. The midplate is preassembled with the rear bearing. This is not model or year specific.