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It uses a driver-operated clutch, usually engaged and disengaged by a foot pedal or hand lever, for regulating torque transfer from the engine to the transmission; and a gear selector that can be operated by hands.Higher-end vehicles, such as sports cars and luxury cars are often usually equipped with a 6-speed transmission for the base model. Automatic transmissions are commonly used instead of manual transmissions; common types of automatic transmissions are the hydraulic automatic transmission, automated manual transmission, dual-clutch transmission and the continuously variable transmission (CVT). The number of forward gear ratios is often expressed for automatic transmissions as well (e.g., 9-speed automatic).Most manual transmissions for cars allow the driver to select any gear ratio at any time, for example shifting from 2nd to 4th gear, or 5th to 3rd gear. However, sequential manual transmissions, which are commonly used in motorcycles and racing cars, only allow the driver to select the next-higher or next-lower gear.A clutch sits between the flywheel and the transmission input shaft, controlling whether the transmission is connected to the engine ( clutch engaged - the clutch pedal is not being pressed) or not connected to the engine ( clutch disengaged - the clutch pedal is being pressed down). When the engine is running and the clutch is engaged (i.e., clutch pedal up), the flywheel spins the clutch plate and hence the transmission.This is a fundamental difference compared with a typical hydraulic automatic transmission, which uses an epicyclic (planetary) design. Some automatic transmissions are based on the mechanical build and internal design of a manual transmission, but have added components (such as servo-controlled actuators and sensors) which automatically control the gear shifts and clutch; this design is typically called an automated manual transmission (or a clutchless manual transmission ).http://www.kapfenberger-schuetzenverein.at/userfiles/3gm30-workshop-manual.xml
Operating such transmissions often uses the same pattern of shifter movement with a single or multiple switches to engage the next sequence of gears.The driver was therefore required to use careful timing and throttle manipulation when shifting, so the gears would be spinning at roughly the same speed when engaged; otherwise, the teeth would refuse to mesh.Five-speed transmissions became widespread during the 1980s, as did the use of synchromesh on all forward gears.This allows for a narrower transmission since the length of each countershaft is halved compared with one that contains four gears and two shifters.For example, a five-speed transmission might have the first-to-second selectors on the countershaft, but the third-to-fourth selector and the fifth selector on the main shaft. This means that when the vehicle is stopped and idling in neutral with the clutch engaged and the input shaft spinning, the third-, fourth-, and fifth-gear pairs do not rotate.For reverse gear, an idler gear is used to reverse the direction in which the output shaft rotates. In many transmissions, the input and output shafts can be directly locked together (bypassing the countershaft) to create a 1:1 gear ratio which is referred to as direct drive.The assembly consisting of both the input and output shafts is referred to as the main shaft (although sometimes this term refers to just the input shaft or output shaft). Independent rotation of the input and output shafts is made possibly by one shaft being located inside the hollow bore of the other shaft, with a bearing located between the two shafts.The input shaft runs the whole length of the gearbox, and there is no separate input pinion.When the dog clutches for all gears are disengaged (i.e. when the transmission is in neutral), all of the gears are able to spin freely around the output shaft.http://deauville.ru/files/3gs-europlex-manuals.xml
When the driver selects a gear, the dog clutch for that gear is engaged (via the gear selector rods), locking the transmission's output shaft to a particular gear set.It has teeth to fit into the splines on the shaft, forcing that shaft to rotate at the same speed as the gear hub. However, the clutch can move back and forth on the shaft, to either engage or disengage the splines. This movement is controlled by a selector fork that is linked to the gear lever. The fork does not rotate, so it is attached to a collar bearing on the selector. The selector is typically symmetric: it slides between two gears and has a synchromesh and teeth on each side in order to lock either gear to the shaft. Unlike some other types of clutches (such as the foot-operated clutch of a manual-transmission car), a dog clutch provides non-slip coupling and is not suited to intentional slipping.These devices automatically match the speed of the input shaft with that of the gear being selected, thus removing the need for the driver to use techniques such as double clutching.Therefore, to speed up or slow down the input shaft as required, cone-shaped brass synchronizer rings are attached to each gear. In a modern gearbox, the action of all of these components is so smooth and fast it is hardly noticed. Many transmissions do not include synchromesh on the reverse gear (see Reverse gear section below).This is achieved through 'blocker rings' (also called 'baulk rings'). The synchro ring rotates slightly because of the frictional torque from the cone clutch. In this position, the dog clutch is prevented from engaging. Once the speeds are synchronized, friction on the blocker ring is relieved and the blocker ring twists slightly, bringing into alignment certain grooves or notches that allow the dog clutch to fall into the engagement.The latter involves the stamping the piece out of a sheet metal strip and then machining to obtain the exact shape required.http://www.drupalitalia.org/node/66059
These rings and sleeves have to overcome the momentum of the entire input shaft and clutch disk during each gearshift (and also the momentum and power of the engine, if the driver attempts a gearshift without fully disengaging the clutch). Larger differences in speed between the input shaft and the gear require higher friction forces from the synchromesh components, potentially increasing their wear rate.This means that moving the gearshift lever into reverse results in gears moving to mesh together. Another unique aspect of the reverse gear is that it consists of two gears— an idler gear on the countershaft and another gear on the output shaft— and both of these are directly fixed to the shaft (i.e. they are always rotating at the same speed as the shaft). These gears are usually spur gears with straight-cut teeth which— unlike the helical teeth used for forward gear— results in a whining sound as the vehicle moves in reverse.To avoid grinding as the gears begin to the mesh, they need to be stationary. Since the input shaft is often still spinning due to momentum (even after the car has stopped), a mechanism is needed to stop the input shaft, such as using the synchronizer rings for 5th gear.This can take the form of a collar underneath the gear knob which needs to be lifted or requiring extra force to push the gearshift lever into the plane of reverse gear.Without a clutch, the engine would stall any time the vehicle stopped and changing gears would be difficult (deselecting a gear while the transmission requires the driver to adjust the throttle so that the transmission is not under load, and selecting a gear requires the engine RPM to be at the exact speed that matches the road speed for the gear being selected).In most automobiles, the gear stick is often located on the floor between the driver and front passenger, however, some cars have a gear stick that is mounted to the steering column or center console.ATLANTAREPAIRTV.COM/images/3-sdu-software-manual.pdf
Gear selection is usually via the left foot pedal with a layout of 1 - N - 2 - 3 - 4 - 5 - 6. This was actuated either manually while in high gear by throwing a switch or pressing a button on the gearshift knob or on the steering column, or automatically by momentarily lifting the foot from the accelerator with the vehicle traveling above a certain road speed.When the crankshaft spins as a result of the energy generated by the rolling of the vehicle, the motor is cranked over. This simulates what the starter is intended for and operates in a similar way to crank handles on very old cars from the early 20th century, with the cranking motion being replaced by the pushing of the car.This was often due to the manual transmission having more gear ratios, and the lock-up speed of the torque converters in automatic transmissions of the time.The operation of the gearstick— another function that is not required on automatic transmission cars— means that the drive must use take one hand off the steering wheel while changing gears. Another challenge is that smooth driving requires co-ordinated timing of the clutch, accelerator, and gearshift inputs. Lastly, a car with an automatic transmission obviously does not require the driver to make any decisions about which gear to use at any given time.This means that the driver's right foot is not needed to operate the brake pedal, freeing it up to be used on the throttle pedal instead. Once the required engine RPM is obtained, the driver can release the clutch, also releasing the parking brake as the clutch engages.Please help improve it by rewriting it in an encyclopedic style. ( June 2020 ) ( Learn how and when to remove this template message ) Multi-control transmissions are built in much higher power ratings but rarely use synchromesh.Usual types are:The first through fourth gears are accessed when low range is selected.
To access the fifth through eighth gears, the range selector is moved to high range, and the gear lever again shifted through the first through fourth gear positions. In high range, the first gear position becomes fifth, the second gear position becomes sixth, and so on. This allows even more gear ratios. Both a range selector and a splitter selector are provided. In older trucks using floor-mounted levers, a bigger problem is common gear shifts require the drivers to move their hands between shift levers in a single shift, and without synchromesh, shifts must be carefully timed or the transmission will not engage. Also, each can be split using the thumb-actuated under-overdrive lever on the left side of the knob while in high range. L cannot be split using the thumb lever in either the 13- or 18-speed. The 9-speed transmission is basically a 13-speed without the under-overdrive thumb lever.Transmissions may be in separate cases with a shaft in between; in separate cases bolted together; or all in one case, using the same lubricating oil. With a third transmission, gears are multiplied yet again, giving greater range or closer spacing. Some trucks thus have dozens of gear positions, although most are duplicates. Two-speed differentials are always splitters. In newer transmissions, there may be two countershafts, so each main shaft gear can be driven from one or the other countershaft; this allows construction with short and robust countershafts, while still allowing many gear combinations inside a single gear case.One argument is synchromesh adds weight that could be payload, is one more thing to fail, and drivers spend thousands of hours driving so can take the time to learn to drive efficiently with a non-synchromesh transmission. Since the clutch is not used, it is easy to mismatch speeds of gears, and the driver can quickly cause major (and expensive) damage to the gears and the transmission.
Since few heavy-duty transmissions have synchromesh, automatic transmissions are commonly used instead, despite their increased weight, cost, and loss of efficiency.Diesel truck engines from the 1970s and earlier tend to have a narrow power band, so they need many close-spaced gears. Starting with the 1968 Maxidyne, diesel truck engines have increasingly used turbochargers and electronic controls that widen the power band, allowing fewer and fewer gear ratios. A transmission with fewer ratios is lighter and may be more efficient because there are fewer transmissions in series. Fewer shifts also make the truck more drivable.Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( June 2020 ) ( Learn how and when to remove this template message ) Gear oil has a characteristic aroma because it contains added sulfur-bearing anti-wear compounds. These compounds are used to reduce the high sliding friction by the helical gear cut of the teeth (this cut eliminates the characteristic whine of straight cut spur gears ).Retrieved 10 March 2020. By using this site, you agree to the Terms of Use and Privacy Policy. This transmission was available only with the 4.11 rear axle ration on Conventional models. The gear shift was located on the steering column. Upload your photos of Chevrolet 3-Speed Synchromesh Overdrive (low reverse) transmission. Please respect copyright. Don’t upload anything you don’t own. It's free and we don't spam. Help the community, write about it and we will improve this page. This site is intended for reference only. Please contact your local dealer for latest info. It may not display this or other websites correctly. You should upgrade or use an alternative browser. I know nothing about these and am having a hard time finding anything about them. It has NO casting on the tailhousing for a mount. The side cover is small with 2 levers. It looks like the overdrive is shifted with a cable.
It justs coasts and the motor won't hold the car back on hills. The cable locks it in or out of OD The can thing is the electric solenoid to self shift into or out of OD. BW made several styles over the decades starting in the 30s. Find the right model on searches, and you should find install info and wiring info.I have also seen this trans set up with an electrical switch on the shifter to give you a six speed. I know the shifter had been there for at least twenty years.What's the govener all about?The description you gave matches the trans your seller says it is. '55 thru '57 Chev had no rear mount on the trans. The engines were mounted at front and at bellhousing, trans hung out in the air. BTW, the 'freewheeling' is only applicable when OD is engaged. With the cable pulled out, disengaging OD, it acts exactly like a 3 speed WITHOUT OD. As for it being a 'decent' trans to run, sure, why not.as long as it is good condition and you want a stick shift. RayYou could wind it up in any gear, lift off, and it would shift into OD automatically.You could wind it up in any gear, lift off, and it would shift into OD automatically. Click to expand. So acceleration is lost in the process of the OD shift. Beyond that, if you consider that most 2nd gear ratios are somewhere around 1.50 to 1.60, then apply the typical BW OD.70 ratio, you end up with 1.05 to 1.12.so very close to 3rd gear 1.0 that it doesn't offer much benefit. Now, of course, when you apply that.70 to 3rd gear, that's when the benefit is realized. Ray. To find out more about the cookies we use and how to control them, please visit our privacy, cookies and data protection page. We offer quality rebuilt manual transmission, parts and rebuild parts kits that are designed to be top of the line. After locating correct unit a link is supplied to provide detailed information on specific kit and parts that are available for your unit.
Information is provided for General Motors 3 speed, 4 speed, 5 speed and 6 speeds manual transmissions. Those from 1955-68 may have electric overdrive. Some of 1964-65 units have larger gears with the same tooth count as the 1940-68 units. Fully synchronized with 30 tooth synchro rings. 1966-69 units may have electric overdrive. It has a four step cluster and all the gears are helical cut. Has case casting number T16-1X. Found in heavy duty applications. Fully synchronized with 36 tooth synchro rings. This is the only GM 3 speed with the same bearing front and rear. This transmission is found in performance applications. Fully synchronized with 36 tooth synchro rings. Same unit as Ford RAT except for a GM bolt pattern to the bell housing. Has R28-20-15 cluster gear. Found in heavy-duty applications. Casting number T10-XX or 13-04 are on passenger side of case. They all have 9-bolt side covers and 36 tooth synchro rings. Reverse shift lever is located in the extension housing, along with main shaft reverse which is a straight cut gear. Some of the early units, found mostly in Corvettes, have a front nut like the Muncie M21. 1984-88 units have overdrive. The side cover has 7 bolts and 2 shifter cams. The synchro rings have 36 teeth and the unit has a 4-step cluster gear. Reverse gears are helical cut and are located in the extension housing. The side cover has 7 bolts and 3 shifter cams. The synchro rings have 30 teeth and the unit has a 5-step cluster gear. Reverse gears are straight cut and are located in the main transmission case. Shifter assembly is attached to the top of the extension housing where the two arms meet. The main case is open at both ends, the bell housing.There is an internal single-rail shift linkage with the shifter mounted on top of the extension housing. Front and rear main bearings are ball type and the cluster gear has a shaft running through it, that is supported by loose needles. Case casting is number 13-53.
Front and rear main bearings are tapered. The cluster gear is solid and is supported on each end by cylindrical roller bearings located in the case. Case castings numbers are 13-51 or 13-52. The Isuzu logo is cast into the left side of the case. Is not found in the Chevy LUV. It has a rectangular cast iron front bearing retainer and a 27 tooth rear output shaft. The front and rear countershaft bearings are both 25x62x17. Side-loaded with either aluminum or cast iron case and used in both gas and diesel applications. All of these units are 3 speeds with Overdrive. All gears on the countershaft are removable except for 1st. Early units have threads on the input shaft and do not have a front seal. Has GM casting numbers and one P.T.O. covers. Non-synchronized 1st with brass synchro rings for 2nd-4th. All main shaft gears ride on bushings pressed on the shaft. The only gears that are removable from the countershaft are 3rd and 4th. Has GM casting numbers and two P.T.O. covers. Non-synchronized 1st gear, synchronized 2nd-4th. There are no brass synchro rings. Casting number is C-9XXXX. All gears, including reverse, are helical cut. See New Process 435 for more information. Casting number is C-9XXXX The bell housing. is not part of this transmission. It has a removable tube that the throwout bearing rides on. The main bearing in this unit is comprised of caged needles in shell races. Loose needles and flat thrust bearings are used throughout the transmission. Casting number is 13-38. Limited parts availability. Isuzu logo is cast into the drivers side of the case. This is found only is GM diesel applications and has a different starter position than the unit that goes into the Isuzu vehicles. Aluminum case with top cover, internal single-rail shift with the shifter mounted on the extension housing. Casting numbers on the case, cover or extension housing are 13-51 or 13-52. 5th gear (overdrive) is located at the rear of the transmission in the extension housing.
The cluster gear is supported on both ends by cylindrical roller bearings. The number on the front cluster gear is DK55836. All five synchro rings are brass. If you are unable, you can check the number of the front cluster bearing. The number on the front cluster gear bearing is 67010BCE.These similar transmissions have three different designs and designations. Teardown is necessary before ordering rebuild kit as the differences between them are integral. It is a fully synchronized Overdrive transmission (including reverse). It may be identified by a tag attached to the P.T.O. cover. The four main supporting bearings in this unit are tapered. Reference Guide Parts illustration. Part of that may stem from the inevitable comparison with the standard three-speed manual transmission of those times, as if the two-speed automatic was grossly handicapped by missing one of those precious three gears. Actually, in many key respects the two speed automatic was very much the equal to the three-speed manual, and then some. Unfortunately, that isn’t necessarily saying much. So before we start comparing apples to oranges, let’s make one thing clear: a three-speed manual will generally (but not necessarily in every parameter) be faster accelerating and more economical in the hands of an engaged driver and proficient shifter then a two-speed automatic. Since the three-speed manuals of yore inevitably had no syncromesh on first, and were rather balky to shift, that excluded a large segment of the population, especially women. Yes, there were exceptions, and women who wanted or needed to drive made do, but not always happily. That allowed drivers to start in second gear from starts, depending on conditions and the car. On large and powerful luxury cars, that was essentially the norm, thanks to their huge engines with enormous flywheels which would even chug a away from a start in top gear without complaint.
Luxury car automakers bragged about the ability of their cars to accelerate from extremely low speeds in top gear without any vibration or complaint. Shifting was something to be endured, but as little as possible, please. Why did subsequent GM automatics revert to one or two geasr? It had a simple fluid coupling (above), which has only two elements and acts somewhat comparably to a mechanical clutch, or more like the centrifugal automatic clutches often used on small scooters and power equipment: when the engine is revved up a bit, the input turbine turns the output turbine via the oil, but there is no torque multiplication. But that’s not the case in the fluid coupling, which takes up rather quickly even at modest rpm, necessitating those four gears in the Hydramatic. First gear ratio in the Hydramatic is 3.66:1, a whole step lower than the typical first gear in a three-speed manual (2.5-2.9:1, typically). Second gear in the Hydramatic is 2.53:1, which essentially equals the first gear on manuals. Third gear (1.45:1) approximates second gear, and fourth gear is direct, unlike modern four-speed overdrive automatics. The Hydramatic felt very different than modern automatics, with a very mechanical feel and abrupt shifts, with the shift from first into second typically occurring part-way through an intersection from a standing start. That explains why the original versions of both the Dynaflow and Powerglide were set up to function as a one-speed transmission that started in High (direct) gear, unless Low was manually selected for extreme situations or those wanting a quicker get-away, at the risk of premature transmission life. Even with one effective gear, torque multiplication at take-off was roughly comparable to first gear in a manual. But for plenty of Americans, that was just fine, if it eliminated the hassle of shifting.
And compared to the distinctly jerky-shifting Hydramatic (“Hydrajerk”), the torque convertor transmissions were perfectly smooth, especially the early ones that never shifted at all. Low gear on the PG was 1.82 or 1.76, which corresponded very closely to second gear on manuals. With its torque converter adding substantial additional torque multiplication to that, the PG had much greater torque multiplication at start than a manual (almost 5:1), and in accelerometer measurements, a PG-equipped car could be faster off the line. So the lack of a “1st gear” really wasn’t really a significant handicap compared to a manual. The PG’s Low gear’s maximum speed was typically between 50 and 70 mph (or more), depending on engine and rear axle ratio; the lower end corresponds to the smaller engines; the top for the biggest V8s. This meant that 0-60 runs were often completed in Low gear only, and PG-equipped cars were typically a second or two slower in that test, compared to a three-speed manual. They both suffer from the same primary shortcoming. The result is a big and painful hole between second and third gear. And at modertae speeds, the Powerglide’s torque converter can still provide some torque multiplication in high gear. But that doesn’t work so well with the six cylinder (or small V8 in a big car or truck), which is what was typically teamed up with the three speed manual. Third is often too low for around-town use, and second is painfully high. And in hauling a load up a freeway or highway grade, a truck or loaded wagon is really handicapped for the same reason. That borders on being a hindrance on a freeway. It allowed me to scoot up the passes (and down) at a faster 45-50 with the engine running at reasonable rpm. Second-OD is the gear I use most around town; its perfect for the 25-30 mph zones. Three-speed manuals are intrinsically deficient, lacking a key intermediate gear, never mind the lack of an overdrive for highway speeds.
A two-speed automatic also has that hole, but it’s actually masked by the torque converter to some extent. During the early-mid sixties, when both Ford and Chrysler were offering three-speed automatics, Chevrolet’s market share against them both surged, despite the missing gear. A four-speed in lieu of the real thing. Teaming a wide-ratio four speed with a relatively long rear axle (low numerically) with a mid-level V8 that had a wide torque band did make for a very nice all-round power train, as fourth would provide almost-overdrive levels of highway engine speed. In any case, Chrysler was late to the game with a four-speed manual, so the TF was certainly faster than its three-speed manual. The optional four-speed in the Corvair transformed it from a sluggish thing, and it undoubtedly was by far the most popular American four-speed car of the early sixties. The other GM Y-Body compacts (Tempest, F-85, Special) also offered four speeds. Now that did perk up the little Falcon six a wee bit, as the three-speed had that miserable hole between second and third. The four-speed should have been standard, as well as on the Corvair. But oval track racing is hardly the same as trying to make good time on hilly and curvy roads, as I did in my father’s 170-equipped (not Hyper-Pak!) ’68 Dodge Dart with its three-speed manual. It handled deceptively well, and the little slant six gave it its all, but the hole between second and third was abysmal in spirited back-road driving. What a let-down to an otherwise excellent car. The rest of Detroit was similarly late in adopting first-gear syncros; VWs had them since 1961. Yes, they stayed around for way too long, but then so did the three-speed manuals. They both were sub-par in a quickly changing world, and frankly, an embarrassment for Detroit; another factor in its decline in the face of imports sporting slick-shifting four, and soon five-speed manuals. Or even better yet, five speed manuals and four speed automatics.
But then Detroit was perpetually stingy when it came to more gears, syncros, disc brakes, anti-sway bars, radial tires, fuel injection and a few other key components, preferring to shower Americans with the really important stuff like vinyl tops, opera windows and loose-pillow seats. That strategy worked for surprisingly long; then it didn’t. Even with automatic, I would’ve thought that an overdrive gear ratio would provide a better cruising speed when driving faster than 40 mph. I like both manual shifting and automatic. Big blocks were common in mildly upmarket cars, which made up for the missing gearing spread at the low end with massive torque at low rpm. In the absence of a lockup clutch, which only a few early automatics had, that would re-lock the stator and you’d get a lot of transmission slip, possibly overheating the converter after a while. It was engaged, electrically, with a pull out knob on the dash. The assist was out and using the car was a miserable experience. Over time with multiple examples of this type transmission I came to shift from 1st to 3rd, then up to second. It seemed to defeat most of the resistance to shifting probably because of non synchro first. Found the 350 to be IMO the best but it was backing up a 350 engine. It was old, ugly, and drove great. In my 77 Impala it gave me right of way that I never could have had with an attractive car. It works well. It was very difficult to drive in SF. I just left it at the hotel and walked or used Uber. Soulless transportation, which is good enough for the week. Then I got into Dad’s ’67, and tried to shift to first for a slow corner, as I had in the ’69. Awful noises ensued. It would go from 0-60 in... well, I never timed it. Still haven’t after owning the car since 1989.At one point, I replaced the 3.70 with a 3.00 because I was doing some interstate driving at the time. It would cruise like a champ on the highway, but was a real turd when trying to pull anything.