According to Nasty Z28.com, 1963 to 1965 M 20 transmissions have 10 splines and 24 input gear teeth, while 1966 and 1967 models have 10 splines and 21 input gear teeth. Yes, but this one will likely out last them all. var num = ""; ATV Tire FAQs Photo by Terry Howe. Serious Skid-Plate protection for the Oil Pan for under 20 or Dana 18. Home-built Box Storage - Mounting Them for Quick Disconnect. All SM420s have a casting on the drivers side. The first one I had was a '72 GMC that I used to pull boats up to 26 ft and travel trailers about the same length in Northern California. with the higher gear ratio i can get more mph in second before i go to third and it's not that noticible to me but i have driving it that way for 15+yrs. they are tough tranny's, it will be hard to tear one up........but it has been done!! Photo by Paul Weitlauf. SM420 casting numbers. Thank you so much for your support thru the years! ATV Lift Installs It also has a 13" clutch. Cheap, effective alternative to undercoating. I LOVE SM465's!    Amazon Business: For business-only pricing, quantity discounts and FREE Shipping. Buick engine. Engine Swaps, ATV World I've driven these trucks with the granny gear transmissions for years. this casting is a date code. right and back of the transmission shift lever. 4 speed granny gear transmission with transfer case (Toano) $750. We have a great online selection at the lowest prices with Fast & Free shipping on many items! Troubled All had a 1:1 ratio high gear. Department of Cheap   Earlier versions SM420 late version with ribbing. Early cases do not Thanks guys. Safety, 25 Top To Do Tips Before The Muncie SM465 is a heavy-duty, four-speed manual transmission built by General Motors for use in light and medium duty trucks from 1968 to 1991. I got my 71 C20 on the road today and this transmission sure leaves alot to be desired. Photo by David Moulton. I had one in a Ford Diesel many years ago. I really disliked it in the beginning but its growing on me. // --> Select this link to see what models that used this 4 Speed transmission. I had that one for I guess 20 years or so. GM 4-Speed Manual Transmission Trucks. Another advantage of the SM420 is it's length is the shortest of Got Pop-ups The casting numbers starting at C-9, followed by four digits. I’m trying to find a 5 speed with no granny gear that would work with this engine. F-100: 1956-1973: Borg Warner T-18: Top loaded heavy-duty 4-speed transmission with cast iron case and shift cover. You need to figure out which is more important, winding it to 5000 RPM for every shift or have a proven sturdy tranny with a granny gear. It is an excellent 4 speed to swap into a Jeep with a Chevy or Buick engine. •Offered in B16, LS and GSR gear … The remaining gear planes are engaged in combination with gear planes 36, 38, and 40 within the auxiliary gear box 14. The finest racing and street gearboxes in the world. There was basically one truck 3-speed and one truck 4-speed during the enclosed drive-shaft 50s years (1950-1954). It is from a Chevy school bus chassis, so it will bolt to any chevy engine. You can just make out the backup light switch to the Motorhome Dodge, GM and Ford. These Muncies have the same serial number format, minus the gear ratio designation, so a spline and gear tooth count must be done. The ribbing was only available on late cases and some ▫ Transmissions SM420 drivers side. partially obscured by the transfer case shift levers. I'm going to be towing a 3000 pound trailer over the Cascades memorial day weekend so I guess we'll see how high she'll wind in 3rd. case attached. When you add the adapter, the Jeep T-18 Major update: Turns out the vacuum advance was not working so the engine was not putting the power out it should have. LiteFoot Track Sys Full Size Chevy 4-Speed Transmission Speedometer Driven Gear, With 21Teeth, Red, 1967-1969. vary from transmission to transmission, but every one I've seen has Maybe if it's all down hill or if I stay in 2nd! Trailering Safety and Trailer Hitch OD. Jeep Technical Info I have had 3 trucks with the 4 speed granny transmission and liked driving them all. ▫ Engines Offroad It was perfect for camper carrying trucks since the granny low was just 4.56-1. Would appreciate any advice! I'm assuming the 67 GMC 4 spd has to be the SM420? This Tech Tip is From the Full Book, GM TURBO 350 TRANSMISSIONS: HOW TO REBUILD AND MODIFY . it should be easy. SM420 front. The SM420 is the older heavy duty, granny, 4 speed transmission used in Chevy and GM trucks. I can't remember what rearend I had in my 65, but I could put it in third, get the rpms up for the race, drop the clutch and run it all the way up to 70 without shifting any gears. bucks! Are there better geared tranys out there? The GOOD thing about putting one of these behind a V-8 is that you CAN lug 'em quite a bit, and wrap 'em out when you want to. Most likely the "E43" in GRANNY GEAR 5 SPEED and yet another manual of these. Manual Transmission Rebuilt. The large cast iron case with large bulge I do know that certain model 435's (mainly newer ones) did have a 4.56 or 4.90 first gear and actually it makes it a much more usable gear. Of course I use my trucks to work with. ATV Repair Lol found the vid of that truck pull...sorry bout the quality.... i love my 465, course its backed by a 400hp+ 327, The 1947 - Present Chevrolet & GMC Truck Message Board Network, http://s14.photobucket.com/albums/a3...ik/NP542%20GL/, http://www.classictrucks.com/feature...short_bed.html, http://67-72chevytrucks.com/vboard/s...d.php?t=426650, http://67-72chevytrucks.com/vboard/s...d.php?t=428035, http://67-72chevytrucks.com/vboard/s...d.php?t=649649, http://67-72chevytrucks.com/vboard/s...d.php?t=590642, http://67-72chevytrucks.com/vboard/s...=493477&page=6. I too am new to the granny 4 speed. The SM420 is the older heavy duty, granny, 4 speed transmission Identify Muncie 1963 to 1967 transmissions. However they are bulletproof! granted today. I dd'ed my GMC for a year and a half before the rockwell exploded, and it came to be second nature. "GM" and the large number starts with a "5". The screw heads are part of the casting. Ran great pulled to go automatic.