Above is the transmission ID tag on a 1970 Corvette. The source serial number is from the CAR the transmission originally went into, NOT the assembly plant. The vehicle identification number (VIN) is a unique identifier for each vehicle (VIN). The two transmission systems manual and automatic, have different working principles. Clean the area thoroughly and use a nice bright flashlight. Casting Number Notes, 3831707 Early side cover; 1963 1965, 3884685 Early side cover; used with 3857584 tailshaft housing, 3950306 Late side cover no switches, 3952642 Late side cover with transmission controlled spark switch, 3952648 Late side cover with transmission controlled spark switch, 335308 Late side cover with neutral safety switch. This is a 4 speed, overdrive unit. In 1962, aluminum units were only used with the 327 engine, but by 1963, all Powerglides had aluminum cases. H = Muncie / 3-speed K = McKinnon / 3-speed M = Muncie / 3-speed N = Muncie / 4-speed O = Saginaw / Overdrive P = Muncie / 4-speed M20 . Found on 76 through 84 models. 3925656 is the casting number for the saginaw used in 68-75 at least. Summit Racing Equipment inventories all kinds of cast-aluminum and steel bellhousings for the Muncie. All rights belong to the entity responsible for the trademark or copyright. It is also a cast iron case. On the Turbo 350, the VIN will be stamped on either the drivers side housing (near the shifter), on the right side of the housing just above the pan, or on a boss behind the bell housing flange on the passenger side of the transmission. On modern models, you can tell which type of manual transmission a car has by looking at the top of the gear shifter. On the Turbo 400, the VIN is stamped on a machined surface just above the pan on the drivers side. Muncie transmissions also tend to get performance improvements such as a gear ratio change and stronger internal parts. The SM465 is an outstanding, heavy-duty truck transmission designed and used in , 3/4 and 1+ ton trucks. But, those built between 1963 and 1965 will not have any rings around the input shaft. I definitely recommend a look at these transmissions, you've got to have a look. These days, the tag looks like P8E17 (Powerglide= type, 8= 1988, E= month, 17th= day). than other boxes. Thank you for working with us. The item 2 Restored GM Saginaw 3 Speed Manual Transmission 10 x 27 Select From 4 Ratios Restored GM Saginaw 3 Speed Manual Transmission 10 x 27 Select From 4 Ratios. Youll not only need to hunt for, and hopefully find the tag, but it needs to be free of enough gunk to be legible. Basically, if you are installing one or the other in a car that will be a nice driver and see only minimal, spirited gear grabbing, both the Saginaw and the Borg-Warner can be a good and less expensive alternative to the more robust Muncie. Whether youre trying to repair your transmission or rebuilding a project car, its crucial to identify the transmission type. There are different ways to determine the transmission type of a GM vehicle. The guys at Anaheim Gear tell us there are seven total Muncie input shaft options. Pre-67 Example: C213N (C = Cleveland Powerglide, February 13, Night Shift) Example: 19N500001. Basically, GM stamped them anywhere they could find a suitable place in the casting. Engine Casting Numbers Explained 1954-1962 Chevrolet, Serial Number/Engine Type/Series Designation, On the flat part of the Distributor Deck you will find a stamped Serial Number. The Saginaw four-speed box is quite similar to both the T-10 and Muncie four-speed transmissions. According to Cangialosi, GM took the basic T-10 design and beefed it up to conceive the Muncie M20 and M21 four-speed transmissions, which arrived in 1963. And keep in mind that not all will sport these grooves. GM produced many transmission variants over the years, we included some of them here, but our main focus is identifying the fluid pans for Powerglide, Turbo 350, and Turbo 400. Input the VIN in a decoder and search. Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks. Identify General Motors' Four-Speed Transmissions 1 groove: First 2.54, Second 1.84, Third 1.32, Fourth, 1.00 2 grooves: First 3.11, Second The code interpretation is (Cleaveland Powerglide, January 23rd, Night shift). Transmissions can be identified in the following manner: Casting numbers : Located on the case, extension housing and side cover (manual). A manual transmission requires the driver to switch gears manually. The 465 is an intellegently designed . This frees up the geartrain. Looks to be from a 68/9 camaro. This is a large reason why some guys will not rely on transmission identification by the input shaft grooves. flashlight. Its case is essentially smooth. Today that seems reasonable however $184.02 1965 dollars adjusted to 2015 dollars is a whopping $1,384.93. However, finding one of these transmissions now at a swap meet or salvage yard is getting harder and harder. However, classic cars usually have manual transmissions. Besides the transmission identification, it also helps to figure out which options was the car ordered with by using a VIN decoder tool. 250 and 292 inline 6-cylinder engines offered, while a 305 V6 was available only in GMC trucks. From the outside, you should be able to make out the number on the metal dash plaque by looking through the glass. Transmission Stuff * Manual 3-speed transmissions * Muncie 4-speed Casting Numbers/Decoding/Identification * Powerglide * Turbo Hydramatic 350 * Turbo Hydramatic 400 * 200-4R/700R4 Overdrive * GM Transmission lengths & oil pan * Automatic transmission operating temps * TH350/TH400 Speedometer Gears Frames * Chevelle Frames Trim Tags Its useful to know the trim of your car so you can easily determine the transmission type. All transmissions with a 26-spline input shaft used a 32-spline output shaft, and all those with a 10-spline input shaft were paired with a 27-spline output shaft. General Motors has produced a myriad of versions of its fabled automatic transmissions over the years, although three models make up the bulk of pre-ECM GM slushboxes; the Powerglide, the Turbo-Hydramatic 350 (Turbo 350), and the Turbo-Hydramatic 400 (Turbo 400). This two-speed box thrives after 71 years and still sees use in motorsports and classic cars. Automatic Transmissions Some transmissions may have a code stamped into their case or a tag riveted to them. If it has a cast-iron case with an aluminum side cover and tail housing, that will mean you have found a Borg Warner. 3. (AODE & 4R70W). 3845122 is the casting number of the transmission case for the 1955-1957 3 speed transmission for passenger cars and Corvettes. THM200-R4 - Used in GM rear wheel drive cars with the 3.8 V6, 305 & 350 Olds and 301 pontiac from 1981 to 1989. The M-22 is distinguished from an M-21 by box FWIW. THM350 - Medium duty 3 speed trans used from 1969 to 1989, Used in Buick, Olds, Pontiac and Chevrolet cars and Chevy & GMC light trucks until 1987. . GM manual transmission identification. The Turbo 400 was GM's heavy-duty three-speed transmission used from 1964 to 1990. From 1967 on, the ID number contained the transmission type or plant prefix, Date (coded below), and a shift code. Expect to find various combinations out there because these high-performance four-speed transmissions have been thrashed, trashed, and rebuilt through the decades. SECOND TRANSMISSION. The length of the unit can also tell you a few things. Enjoy the forum? THM250 - Used in small 4 cylinder cars (Vega, Sunbird, Monza) from 1973 to 1981 and some Nova/Camaro/Chevelle 6 cylinders in 1974 & 75. Need a little help in the ID of a GM 3 speed trans I picked up. After 1967, GM switched things up and changed the code structure. The 1956 through 1962 Corvettes only used the aluminum versions. The M22 Rock Crusher would come later to accommodate the heavy twist of Chevrolet's big-blocks in the mid-1960s. Good, solid, rugged construction makes it a terrific drop-in for around $100. For a better experience, please enable JavaScript in your browser before proceeding. Standard Borg Warner H.D. Use the shifter to shift gears and note the number of times it shifts. fileslib. The T-10 four-speed was an evolution of the T-85 three-speed transmission, with both of these transmissions being quite similar in appearance. Chevy Hardcore NEWSLETTER - SIGN UP FREE! During the run of General Motors inclusion of four speeds in their cars, there were three variations possible. Depending on how you ordered your muscle car in the 60s and early 70s, you might have even benefitted from the famous Muncie transmission. Aavailable in a 3 speed auto or 4 speed manual transmission. Now, lets explore GM transmission identification, the different methods, and more. makes this job easier. You can check online auto repair websites, as some have free decoders. Finding the ID tag can be extremely difficult on the Turbo 35o particularly because, its probably been lost. MX3 Another Turbo 350 C code. The Muncie four-speed was produced in two ratios: the wide ratio (M20) and the close-ratio (M21). When you find a used four speed, a Saginaw and Borg Warner transmission will likely be flash rusted because of the cast-iron construction. The main case will sport a seven-digit casting number (found above the US Patent No), which is not a GM part number. different casting number, which is 10168588. We promise not to use your email address for anything but exclusive updates from the Power Automedia Network. It also has the numbers "4.3" cast in the block itself, which makes it easy to spot as the smaller 3.74-inch-bore block. There is no leaking coming from the front seals, rear sears or oil pan. Manufacturer Part Number. The World's Best Chevrolet and GMC Club! The first letter is almost always F since most GM engines were made in Flint, Michigan. We are dedicated to giving you the technical support you need, when you need it! The 4L80E would be the "electronic" model. Before 1967, General Motors included extra information such as the plant code, shift code, and date of production on the ID tag. Starting with the 1966 models, the wide ratio versions got two rings around the input shaft, and the M22 input shaft had no rings and looks like a 1963 through 1965 wide-ratio input shaft. This decreased helix angle of the gear not only created a stronger gear set, but it also produced a substantial amount of gear whine which is highly noticeable when driving the car. The best way to identify a GM automatic transmission is by observing the transmission pan. The Muncie was used in all high performance applications until the Borg-Warner Second Design Super T-10 began replacing it in 1974. Check through the information for your transmission identification. hey Bob .I wish I could help out with your numbers on the trannys. 3854728. The first and most obvious has to do with the size of a cars engine. The casting number 3925660 denotes this as a 1968 1970 Muncie with a 1-inch cluster shaft. This list includes some GM transmissions. In 1974, the two-speed box then went to the great scrap heap in the sky. the angle of the gear teeth. For example, a GM vehicle from before 1967 has an ID tag that looks like C123N. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. The Turbo 400 was GMs heavy-duty three-speed transmission used from 1964 to 1990. While the big-block vs. small-block variable is one that has two groups of passionatefollowers, the other reflects the way in which the driver selects transmission gears. Many GM trannys had the VIN stamped on the maincase on the flange where it attaches to the tailshaft, but some of the later Saginaws had a pad machined into the case just for stamping the number. Also, there were some input shafts produced by the aftermarket and General Motors that have no identifying rings on them. Has the casting # of 3925656. Note the single groove, meaning an M21 close-ratio. We have salvaged more than one Saginaw from cars like the Vega and Monza. A = Jan, B = Feb, C = Mar, D = Apr, E = May, H = Jun, K = Jul, M = Aug, P = Sep, R = Oct, S = Nov, T = Dec. On the far right is the M22 26-spline input shaft. The Turbo 350 quickly became known for its strength, versatility, and compactness. 1962-1973. The Muncie has probably been the most popular transmission among the hot rodding set since its inception in 1963. GM's goal with the Muncie four-speed was to produce a better shift employing larger synchro cones. Measure the pan and examine the shape. THM200 - Light duty, "metric" 3 speed transmission. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! They are notoriously very hard to read and often people make the mistake of thinking a '3' is an '8'. 3.55 geared and higher (numerically lower) cars used the wide ratio gearbox. Thanks Dec 11, 2012 #2 G Gary S Administrator Lifetime Gold Member Apr 14, 1999 24,823 3925658 does not match any casting numbers in my books. In modern cars, you can quickly identify the 6-speed and 5-speed transmission applications. Nowadays, most drivers are more familiar with automatic cars, and manufacturers mostly use automated transmission systems. New Process Gear NP435 - 4-speed longitudinal transmission used in a select handful of 67-72 GM pickups The most common GM 4-speed transmission types or groups are Muncie, Saginaw, and Borg-Warner. It'll be marked 375-THM on the bottom of the tailshaft housing. 3952645 shows up as the sidecover casting number for the 1972 Saginaw 3 speed. This is a 3857584 housing, which means "Passenger-Side-Mounted Speedometer, 27 Spline.". K 170. 1981-1990. Check the car flooring, and if theres a clutch pedal, the transmission is manual. The 1964 through 1968 Muncie side covers had a stud coming out of the side cover that secured the linkage arm via a nut. Because the Muncie has so much in common with the T-10 and even similar Saginaw boxes, it is easy to get this guy mixed up with non-Muncie units. From 1971 through the end of production in 1974, the M20 got the 26-spline input shaft. The basic design and operation theory of the gearbox changed little during that time, though several design upgrades and modifications were made during the total production run. Other than the shape of the fluid pan, another key way to identify the Turbo 350 is by the vacuum modulator. (on manual trans). How to identify and decode chevrolet manual transmissions. The source serial number contains additional information such as model year, division identification number, manufacturing plant, and production sequence. Afterward, you can count the bolts securing the pan. If you have looked very carefully and find no numbers there, chances are your block is classified as a Replacement Block The transmission pan is one of the most precise methods of identifying a transmission. Some transmissions have a code stamped onto them. The materials used in case construction of a Muncie/Chevy four-speed mean that if you find one of these gear boxes in a shed or barn, the Muncie will probably be smooth and covered in grease and/or oil, while a Borg Warner or Saginaw transmission will usually be coated in a light layer of rust. If you dont know where to check, the transmission usually stays around the area of the rear tires. The easiest method of GM automatic transmission identification is to examine the transmission pan. 1993 and Newer (4L60E), 1980-1991 (AOD) Note partial VIN stamped at the bottom. If you find an M22, you have the ultimate Muncie designed for the high torque of a big-block that will bolt to your small-block. Its no secret that the Saginaw and Borg Warner transmissions were not built to handle the kind of power that a Muncie transmission could withstand. Once you identify the pan, count the number of pan bolts for confirmation. M38 Standard Turbo 350 manufactured from 1976 to 1981. Sep 23, 2019. Transmission identification may be determined by finding the transmission application code in the following tables. For 1971-'74, a larger diameter, 32-spline mainshaft was employed along with the corresponding yoke. Almost all Muncie transmissions were delivered with a groove(s) on the input shaft and counter gear. To add a little confusion to the mix, there were Borg-Warner Transmissions that feature aluminum cases and cast-iron side covers. The transmission identification number or source serial number (chassis VIN) is usually located close to the transmission code.