Parts Information Have a good trip - with John Deere clutches! The clutch disc is the central connecting element of the clutch. Together with the flywheel and the clutch pressure plate it forms a friction system. This system engages and disengages the engine from the transmission, enabling the driver to start, stop and shift gears. The clutch transmits the engine drive torque to the transmission input shaft through the hub splines. But the clutch disc ensures much more, such as a smooth drive without juddering when starting or reversing fast gear changing of the transmission... gentle clutch engagement without annoying rattling noises keeping away engine vibrations from the transmission John Deere clutch disc - special features for greatest reliability! Main damper spring Idle damper spring Cushion segment Clutch facing Torsional damper assembly Overview of respective John Deere clutch disc part numbers Part No. Tractor Series Remarks AL120018 40, 50, 55 AL70272 40, 50, 55 For heavy duty conditions The clutch disc is a critical component to ensure long service life of the whole clutch system. It provides smooth engagement and dampens engine vibrations. John Deere compared two non-genuine clutch discs with the genuine John Deere parts AL120018 and AL70272. Let s see the results of the testing and the differences found! 1
Overview of genuine versus non-genuine clutch discs tested: AL120018 Genuine John Deere clutch disc AL70272 Genuine John Deere clutch disc Results of quality checkup: Genuine: The main dampers are springs located inside the torsional damper assembly. They damp vibrations between the engine and the transmission to ensure smooth engagement. To reach an optimum damping level and to avoid transmission rattling noises, an individual set-up of the clutch system in accordance with the tractor specifications (e.g. weight) respectively the engine (e.g. torque) is mandatory. Main damper springs Non genuine: Compared to the genuine clutch discs, the non-genuine parts show a considerable deviation of the stop torque. This is because the dampers and the complete clutch disc are not set-up in accordance with the specifications of the John Deere tractor. The clutch discs do not comply with John Deere specifications. The effects are bad damping characteristics of the whole clutch and bad isolation of engine vibrations towards the transmission - with a high risk of enhanced transmission wear. 2
Genuine: The idle damper springs are also situated in the torsional damper assembly. Together with the main damper springs they provide optimum damping of engine vibrations to ensure smooth engagement and eliminate gear rattle at idle speed. Non genuine: The clutch discs do not feature idle damper springs at all! Massive rattling noises Genuine clutch disc Idle damper springs Genuine John Deere clutch with idle stage damper springs features only main damper springs Genuine: The cushion segments ensure soft clutch engagement without jolts and a smooth start-off - for an excellent start-up behavior and a high level of driving comfort. Non genuine: The segment of the non-genuine clutch disc corresponding to AL120018 is too short and the non-genuine clutch disc corresponding to AL70272 does not feature a segment at all. Bad start-up, increased wear and reduced driving comfort. Cushion segment Genuine clutch disc AL70272 3
Genuine: Reduced wear due to an optimized material treatment - use of case hardened material (drive disc and retainer plate) resp. inductive hardened material (hub). Material quality e.g. hub, drive disc and retainer plate Non genuine: The clutch disc components do not feature specially hardened high quality material. Increased wear due to poor material quality particularly of the hub and the torsional damper - reduced lifetime. Genuine clutch disc AL120018 Genuine hub features specially hardened high-quality material Non-genuine hub features soft and not specially hardened material which wears out much more rapidly Genuine: John Deere clutch facings are adapted to the application. For example, the heavy duty disc AL70272 features ceramic pads with special temperature-resistant characteristics. The clutch facing material ensures optimum resistance against wear and a constant high friction coefficient up to temperatures of 600 C. In addition to this the genuine part features a specific groove pattern which is especially important for heavy duty applications - for excellent disengaging characteristics. Material e.g. clutch facing Non genuine: The clutch facings show poorer material quality with a lower friction coefficient factor. The clutch facings do not feature a groove pattern. A high friction coefficient is essential for the reliability of the clutch disc. By wrong use of the clutch, the lower friction coefficient bears the risk of clutch slipping. In addition, the poorer material properties of the clutch facing lead to increased wear and as a result a shorter service life of the clutch disc. The missing groove pattern leads to poor disengaging characteristics. Genuine clutch disc AL70272 4
Workmanship standards e.g. spring windows Genuine: The windows in the torsional damper assembly feature folds and are perfectly adapted to the shape of the idle and main damper springs. Therefore they ensure optimum positioning and guidance of the springs throughout the service life - for best damping characteristics and smooth clutch engagement. Non genuine: The shape of the spring windows is not optimally adapted to the idle and main dampers and shows a low standard of workmanship without folds - increased risk of wear and fallen out springs. Negative impact on damping characteristics and clutch engagement. Genuine clutch disc AL120018 Dimensions e.g. torsion housing Genuine: For a reliable operation of the disc it is necessary that all parts of the clutch disc comply with John Deere specifications - to ensure a reliable function of the whole system. Non genuine: Compared to the requirements of John Deere specifications the non-genuine torsional damper assembly of AL70272 shows a dimensional deviation of more than 1 cm. The deviation in dimension has a negative impact on the interaction of all components. The specific tasks of the disc, e.g. transmitting the engine drive torque to the transmission, can not be fulfilled as reliably as it should be - especially for heavy-duty applications. Benefits of genuine John Deere clutches: Matched to the specific engine torque Comfortable engaging/disengaging of the clutch - for smooth starts No annoying rattling noises when engaging or disengaging Long lifetime of the clutch due to optimized material treatment according to the application High level of driving comfort throughout the whole service life of the clutch 5