gm 3 speed manual transmission casting number decoder

With an old GM 4-speed manual, you have to observe the transmission system side profile. But in non-performance applications, they were still a good Chevy four-speed transmission. In the middle is the M21 countershaft and input shaft. The transmission underwent little change, the major difference was a switch from cast iron to an aluminum casting in 1963. theYear=now.getYear() That is why we offer multiple ways for you to search for your transmission. The M-20 wide ratio, the M-21 close ratio, and the "Extra heavy 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. The NHTSA has some VIN check tools that can assist in identifying transmission types. In order to correctly identify a Muncie four-speed transmission, several visual clues are needed, and those cues involve the casting numbers on the case, side cover, and tailshaft. Author and technician Paul Cangialosi tells us the original U.S. patent for the Muncie four-speed was filed on November 29, 1957, and approved May 7, 1963. He tells us both the M20 wide-ratio and M21 close-ratio transmissions were first offered in 1963 . It functions correctly. Automatic Transmissions Some transmissions may have a code stamped into their case or a tag riveted to them. First, you must check whether its a manual or automatic transmission. Transmissions have RPO numbers, usually beginning with "M". We'll send you the most interesting Chevy Hardcore articles, news, car features, and videos every week. When other companies started making automatic transmissions in the 1950s, GM already had four in-house. When it shifts from 1st to 2nd its got a really smooth shift and it puts a smile on your face. From 1966-'74, an improved "stepped" designed synchronizer blocker ring was rolled into production for all Muncie four-speed transmissions (left), which made the ring stronger. If you have a 1963 Muncie that needs an input shaft bearing retainer, all is not lost if you can't find the 1963 aluminum bearing retainer. gross weight. Your HTML, scripts like Google Ads, images/links, go right here. Dave Cruikshank is a lifelong car enthusiast and an editor at Power Automedia. You need to look . The Saginaw four-speed box is quite similar to both the T-10 and Muncie four-speed transmissions. If it is still attached, the ID can be found in several places on the transmission: If youre under a car trying to read this, it can be tough. tailgate or cargo doors. On the right is the M22 countershaft with 27-teeth. The transmission pan is a wealth of knowledge because it has various inscriptions concerning the transmission. I definitely recommend a look at these transmissions, you've got to have a look. Prior to 1967, transmission ID numbers contained the plant prefix code, month and date of production (expressed numerically) and a shift code (D = Day, N = Night). GM Turbo 200 and 200C: 3 Speed Transmission. Use the following information to compare physical description of your Chevrolet or GMC manual transmission in order to identify what model transmission is, MySpace !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); You can find the serial number on the bottom left of the transmission data plate. Making this separation makes the job easier. 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. 10. Before using any method to find your transmission type, you should find out if its a manual or automatic transmission. Shown here is the M20 10-spline wide-ratio input shaft and counter gear. On the left is the M20 countershaft and 10-spline input shaft. The Turbo 400 was GMs heavy-duty three-speed transmission used from 1964 to 1990. This is usually a 7 digit number and each letter/number is about 1/2" tall. Found on 76 through 84 models. The casting number 3925660 denotes this as a 1968 1970 Muncie with a 1-inch cluster shaft. Next, carefully raise the vehicle with a jack. FORD (336) BORG-WARNER T-10, GM AS-3 (410) *MUNCIE Shaft Identification:. And keep in mind that not all will sport these grooves. THM700-R4 - 4 Speed transmission used in GM cars and light trucks with the 2.8, 3.1, 4.3, V6, Chevrolet built 305, 350 and 454 engines from 1982 to 1992. 1969-1986. Depending on how you ordered your muscle car in the 60s and early 70s, you might have even benefitted from the famous Muncie transmission. We need to make note that the early Muncie transmissions offered between 1963 and 1965 utilized a 7/8-inch countershaft in the cluster gear, and those manufactured between 1966 and 1974 used a 1-inch diameter shaft. However, neither compares to the Muncie in terms of strength. From 1971 through the end of production in 1974, the M20 got the 26-spline input shaft. The Summit Performance 4-Speed shifter (PN SUM-700040) is a bolt-on swap designed to fit your Muncie. A typical Saginaw assembly date stamp would be S313 indicating Saginaw trans produced March 13. be noiser (whines or howls almost like a blower, which is why it's called a "rock crusher") It was standard equipment on large displacement, high-torque engines, and is generally found in trucks, and full-size GM rear-wheel-drive cars. This is when you have to remove the side cover to see what's inside. The vehicle identification number (VIN) is a unique identifier for each vehicle (VIN). the angle of the gear teeth. 12. fileslib. The Turbo 375 was a version of the transmission used from 1972 through 1976, in small displacement cars. The vacuum modulator is also a way of identifying GM transmission type after checking the pan and counting the bolts. Before you can identify the transmission pan, you have to access it from under the car. Performance parts such as Hurst shifters were just as readily available for 3-speeds as with 4-speeds. The Turbo 475 was an extra-heavy-duty version and was found in larger trucks from 1971 on. 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. In 1974, the two-speed box then went to the great scrap heap in the sky. hey Bob .I wish I could help out with your numbers on the trannys. Steel tag on the passenger side: Powerglide transmissions were cast with the word Powerglide along the body, Assembly Date Code Stamping can be stamped anywhere, Chassis VIN Number stamping or source serial number- beginning in 1962. Comparison images courtesy of Hurst Shifters. The M20 and M21 transmissions produced from 1963-'74 are easy to identify in both wide- and close-ratio units. Main case#3925656 Extension#3925658 Side cover#6261886 also has a date 11-13-78 or 11-13-70 hard to make out . Expert advice on car parts, maintenance, and repair. Standard Borg Warner H.D. This machined flat area has serial numbers If you examine the 1966-'70 wide-ratio M20 input shaft, there are two grooves cut amid the 10 splines. WE ARE READY TO SUPPORT YOUMon - Fri 9:00am - 6:00pm EST. Some transmissions have a code stamped onto them. The problem with checking the owners manual is that a junkyard find wouldnt have one. than other boxes. 2.1Date codes 3GM transmissions, including Muncie M20, M21, M22 4Automatic transmissions 4.1AMC automatic transmissions, 1972-'06 4.2AMC automatic transmissions, 1955-'71 4.3Jeep automatic transmissions, 1971-back 4.4Transmission dimensions 4.4.1Ford 4.4.2MOPAR 4.5Ford automatic transmissions 4.5.13-speed identification 4.5.24-speed identification This was used in A-body and F-body cars and Corvettes into the early 80s. Many enthusiasts mistakenly refer to all Muncies as Rock Crushers, and this is just not appropriate. The 1963-'65 M20 input shaft will not have grooves. and will have no numbers stamped on that deck. It's worth the price of membership! The 1956 through 1962 Corvettes only used the aluminum versions. Finding the ID tag can be extremely difficult on the Turbo 35o particularly because, its probably been lost. Note partial VIN stamped at the bottom. They used -E to distinguish the electro Hydra-Matic transmission from other non-electronic ones. How to identify and decode chevrolet manual transmissions. Generally able to handle up to 400 foot pounds of torque. theYear=theYear+1900 The Turbo 400 has a very distinct fluid pan. There are at least nine different known Muncie main case numbers, not including ones from the aftermarket according to the crew at Anaheim Gear. Effective October 21, 1968, an additional letter was added to the plant prefix number to help identify the gear ratios in Muncie transmissions. Early Muncie 4-Speed Identification. Vehicles leaving the factory with an axle ratio of 3.55 and numerically lower gears, typically incorporated a wide-ratio transmission. The bearing bore size was also one year only with a #6207-style input shaft bearing, according to Cangialosi. You can find out if your GM model is automatic by using the same method. There is no real performance potential in the smaller 4.3 version, and it should be avoided or replaced with the larger LT1/LT45.7L engine if high performance is the goal. The 26-spline input shaft came into production later in the 1970s for the M20 and M21. While casting numbers are a definite guideline for identification, a quick, somewhat accurate way to quickly identify Muncie transmissions involves the input shafts. // ]]> Ning Network Name Goes Here. According to Cangialosi, two companies, Borg and Beck and Warner Gear, merged in 1928 to form BorgWarner. One more way to identify the Muncie is via stamped codes in the case, which indicate when the transmission was built at Muncie (see How To Read Muncie Build Date Codes chart). From 1950-1973, most GM divisions used the iconic Powerglide transmission. Not only is the diagram below helpful for identification purposes, but is a great visual source to see if you have enough room for a swap you might be contemplating. The 17-character number is a form of code that identifies the vehicle's specifications. May 31, 2006. Serif is a seasoned automotive enthusiast with a passion for cars. General Motors used different transmission pan shapes and bolts for its models, so this method requires some knowledge of the pans. The large-bore Muncie came into production in 1964-'65 and became the standard from then on through the end of production in 1974. This list includes some GM transmissions. 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

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