Editing Rearend identification

{{develop1}}<br> ==Introduction== There are several ways to tell what the type/size/application of a rearend. Besides visually checking and comparing rearends to one another, there are casting numbers, build codes and dates displayed or cast/stamped in various locations on the rearend and elsewhere. These all can be used to help ID a rearend. ==Casting numbers== Many if not all rear end housings will have some sort of casting number or ID cues to identify it. If the RPO decal is present (newer vehicles) or the broadcast or "build" sheet is available, it can show what was originally in the vehicle. Sometimes body/fender/cowl tags contain coded info that may list specifics on the rearend. ==Axle codes== [[File:Rearaxlecode1.jpg|thumb|left|400px|Example of GM stamped axle code]]GM axles are stamped on the axle tube (and sometimes the center section) with codes for the year and ratio. Sometimes the casting numbers can also be used to show whether an axle housing is a limited slip differential (LSD) or not. <br style="clear:both"/> Some sites with ratio and axle code info are: *[http://www.novaresource.org/axle.htm Axle Codes] from novaresource.org *[http://www.thecamaro.com/Decoding/Chevy-Axle-Rear-End-Decoding/ Chevrolet Rear Axle Code Identification and Decoding] from thecamaro.com *[http://www.thecamaro.com/Decoding/Chevy-Axle-Rear-End-Decoding/Chevy-Full-Size-Rear-Axle-Codes.php Chevrolet Full Size and Impala Rear End/Axle Assembly Codes] from from thecamaro.com *[http://aplsweb.com/Topics/Differential.htm Various tid-bits, et cetera] from aplsweb.com *[http://tech.oldsgmail.com/axle_useage.php GM A-body codes] from tech.oldsgmail.com *[http://www.gnttype.org/numbers/axcodes.html Gear ratio info] from gnttype.org Ford rear ends sometimes had tags under one of the carrier bolts that had the ratio and a code for being a LSD or not. Ford also used an axle code on the body tag on some models. ==Date codes== The date code format can vary, but sometimes the date code is a letter followed by two or three numbers. The letter is the month. The next number or two numbers will be the day of the month. The last number is the last digit of the year. :Example: '''C124''' :*C = March (A = Jan., B = Feb., etc.) :*12 = day of the month :*4 = year ending in 4, i.e. 1964, 1974, 1984, etc. ==Axle dimensions== ===Axle flange dimensions=== [[File:Rear end axle flange id.jpg|thumb|left|600px|Axle flange dimensions from [http://moparinterests.blogspot.com/2010/09/mopar-rear-axle-dimensions.html Moparinterests blogspot.com]]] <br style="clear:both"/> ===GM Hotchkiss (removable carrier) type=== The Hotchkiss type removable carrier rear end was used by GM for a number of years in passenger cars before GM started using the Salisbury type integral carrier rear end. The Pontiac/Olds versions from the later '50s were a drag racing mainstay for many years- even in front engined Top Fuel dragsters and Altereds. ===1955-'64 carrier casting numbers=== 3 series (2.73:1- up): '''410408N''' 2 series (2.56:1- down):'''410409N''' The Chevy version used various tags to designate the ratio. [[File:GM DIFF ID TAGS.jpg]] <br style="clear:both"/> ===Casting numbers and casting codes=== *The casting number for a 1956 case should be 3707306 *The casting number for a 1957-'61 non-posi center case should be 3725899 *The casting number for a 1957-'61 posi center case is 3743833 *The casting number for a 1962-'64 posi center case is 3789812 The above are all casting numbers for passenger cars. These casting numbers are the same for Corvette rearends because the rearends were cast and assembled at just two facilities: the Detroit Gear and Axle plant and the Buffalo, NY plant. The only thing that would be different between the same year Corvette and a passenger car rearend center section would be the stamped (not cast) two letter code on the passenger side of the case. The code designates the gear ratio. ==Ford== *[http://www.fordification.com/tech/rearends_ford01.htm Ford Rear Axle Assembly Identification] Stamped axle codes Ford used a vast array of rear ends over the years. Besides the codes stamped into the axle tubes, some carried ratio and/or posi tags as well as the vehicle having a plate containing coded info on the rearend. Below are photos of some of the more common rear ends for visual reference and comparison: ==Removable (Salisbury type) carrier== [[Image:9inch.jpg|thumb|left|400px|Removable carrier, rear view.]] <br style="clear:both"/> ====ID==== An easy way to tell the difference between the 8-inch and the 9-inch Ford differential is that on an 8-inch, a socket will fit on the lower nuts seen in this picture. Since the pinion centerline is lower on a 9-inch, a wrench is needed to gain clearance. ===8 inch=== {| |[[File:8inford.jpg|thumb|600px|center|8 inch Ford front view]] |[[File:9inchrear1.jpg|thumb|center|400px|8 inch Ford differential details. Note the accessibility of the bottom bolts indicating it's not a 9 inch.]] |} ===9 inch=== One of the strongest Ford rear end was the 9". Still one of the best rearends to modify or use in stock form to handle big horsepower. [[Image:DSC02404.JPG|thumb|left|500px|9 inch Ford rearend]] <br style="clear:both"/> ===9-3/8 inch=== Removable carrier. Found in some Lincoln, Mercury and Thunderbird. ==Non-removable carrier== ===8.8 inch=== {| |[[File:8.8 truck.jpg|thumb|center|600px|8.8" rear end in a Ford F150 4X4]] |[[File:Ford 8.8 w damper weight.jpg|thumb|center|380px|8.8" rear end with damper weight attached]] |} ===8.7 inch=== Non-removable carrier. Found in Granada, Monarch 1977 to 1978. [[Image:87rear.jpg|thumb|left|500px|8.7 inch Ford rear end]] <br style="clear:both"/> ===7.75 inch=== Non-removable carrier. Found in Fairlane. ===7.5 inch=== Non-removable carrier. Found in light duty applications such as six cylinder Falcon, Fairlane and 170 cid Maverick (Mavericks powered by 200 cid, 250 cid and 302 cid engines had the 8-inch differential). ===7.25 inch=== Non-removable carrier. Found in Falcon, Econoline, Fairlane, Comet. ===7 inch=== Non-removable carrier. Found in Falcon. ===6.75 inch=== Non-removable carrier. Found in some Pinto and Mustang II. [[File:Pintorear.jpg|border|450px]] ===Columbia 2-speed rear end=== More of an overdrive unit than an actual rear end. Included in the Ford section since it was offered as an option on '30's to '40's Fords. ==General Motors== ==GM diff covers== [[File:Gm axle covers.jpg|left|frame|GM diff covers]] <br style="clear:both"/> [[File:GM 10bolt id.jpg]] [[Image:10bolt.jpg|thumb|left|500px|10 bolt 8.5 inch GM corporate rear end]] <br style="clear:both"/> *[http://chevellestuff.net/qd/index.htm Axle codes by year] ===10 bolt=== ====8.2" applications==== The 8.2" rearend was used through 1970 in the B-body (Impala) and F-body (Camaro) cars. The 8.2" was used through 1971 in the X-body (Nova) and through 1972 in the A-body (Chevelle). ====8.5" applications==== The 8.5" corporate 10-bolt rearend began production in 1971 to replace the 8.2" and 12-bolt rearends. There was simultaneous use of the 8.2 and 8.5 during the changeover period, like in the Nova. ====10 bolt ID==== If you don't have the codes on hand to identify if a 10 bolt rear end is an 8.5" or not, you can measure the distance between the very bottom bolt for the cover and the next adjacent bolt (either right of left), it will be 3-3/4" for a 8.5" and 3-1/4" for a 7.5".<br> {{Note1}}Some installation kits for the 8.5" and 7.5" use ring gear bolts with a 5/8" head, so if someone has rebuilt the rearend with one of these kits the bolts will have smaller heads than the original bolts. Another [http://www.hotrodders.com/forum/need-id-gm-10-bolt-163067.html#post1571160 tip] is to check the size of the pinion nut. The 8.2" uses a 1-1/8 inch socket on the nut and the 7.5" and 8.5" use a 1-1/4 inch socket. That is as long as they have a OEM type nut on them. There are usually two distinctive lugs cast into the bottom of the 10 bolt rear end housing. These lugs are arrowed in the image above. The ring gear of the corporate 10 bolt is secured by 7/16-20 '''left hand''' thread bolts having a 3/4" hex head on them; there will be ten bolts holding the ring gear to the differential. The ring gear is (as mentioned) 8.5" diameter and the pinion shaft diameter is the same as the 12 bolt at 1.625". The 8.5" pinion has 30 splines. The 8.2" diff will have 10 bolts holding the ring gear on the diff, the bolts will have a 9/16" hex head and be right hand threaded. The 8.2" uses ten 3/8-24 right hand thread bolts to hold the ring gear on the diff. The pinion diameter is 1.438", having 25 splines. The 7.5" diff will have the ring gear secured with 10 bolts that are 7/16-20 LH thread, like the 8.5" corporate rear end. However, the ring gear diameter is smaller than the 8.5" differential. ====10 bolt carriers==== The corporate 10 bolt 8.5 inch rear end uses two different carrier series depending on the rear gear ratio: *2.56 and higher gears ("higher" gears have lower numbers, like 2.41, 2.29, etc.) go on the 2 series carrier *2.73 and lower ("lower" gears = higher numbers, like 3.08, 3.23, etc.) go on the 3 series carrier A 3-series gear can be installed on a 2-series carrier by using a [http://www.summitracing.com/parts/MRG-908A/?rtype=10 ring gear spacer], but this is not advised for stick shift applications, or if there's a lot of traction, HP and/or weight involved. [[File:Copo 10-bolt ring gear spacer.jpg|thumb|left|450px|Mr. Gasket p/n 908A ring gear spacer for the 8.5" GM 10-bolt 2-series carrier]] <br style="clear:both"/> ==Mopar== [[File:Dana tags.jpg|left|thumb|350px|Dana diff tags]] [[File:Dana axle covers.jpg|left|frame|Dana diff covers]] <br style="clear:both"/> *[[Mopar rear axle spotter's guide]] *[[Mopar tapered axle rear brake conversion]] ==AMC== ===ID=== AMC axle codes are stamped on the differential casting between the cover and the tube weld hole on the passenger side) beginning in 1970 for the AMC 20 series rearend, 1972 for the AMC 15 series. First four letters/ratios are 1970 rear axle codes stamped on the differential housing cover flange at about 3 o'clock: A = 3.54:1 B = 3.15:1 C = 2.87:1 D = 3.91:1 E = 3.58 (12/43) F = 3.08 (13/40) G = 3.31 (13/43) H = 2.73 (15/41) J = 2.37 (19/45) The 15 series had 10 bolt oval cover with drain plug center right. ===15 series rearend=== The AMC 15 series rearend has a 7-9/16" ring gear. It was used in 1965 and earlier models with 196 ci or 199 ci inline 6 engines. The small cars (cars other than those listed below as "big car") used the AMC 15 rearend with inline 6 engines, AMC 20 rearend was used with V8 engines. The AMC 20 rearend could be ordered in fleet cars with inline 6 engines. ===20 series rearend=== The big cars (Ambassador, Classic, Rebel, Matador and Marlin) used the AMC 20 rearend with 232 ci inline 6 and bigger engines. The series 20 was used in Jeeps as well as AMC passenger cars. A Jeep 20 series rearend would have a 5 on 5" bolt pattern. Passenger cars used the 5 on 4-1/2" wheel bolt pattern. [[File:Amc 20 series rearend.jpg|thumb|450px|left|20 series under a 1966 Rouge]] <br style="clear:both"/> ==Resources== *[[Gear ratio check]] *[[Limited slip and locking differentials]] *[http://www.crankshaftcoalition.com/wiki/Ford_9-inch_rear_ends Ford 9 inch rearends] *[http://chevellestuff.net/qd/generic_rear_axle_info.htm Generic rearend info] from chevellestuff.net *[http://www.nastyz28.com/2gcog/rearaxle.html Camaro rear ends] *[http://www.novaresource.org/axle.htm Nova rear ends] *[http://www.chevelles.com/years/70/70rearcodes.html Chevelle rear ends] *[http://corvette-world.com/corvette_1968-82_Rear_Axle%20Ratios_Identification.php Corvette rear ends] [[Category:Identification and decoding]] [[Category:Rearend]]

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