Manual Transmission - 6-Speed Manual Transmission

Description and Operation Construction features on the differential side   Item Part Number Description 1 - Differential 2 - Reverse gear idler 3 - 1st gear wheel 4 - 1st/2nd gear synchronizer clutch 5 - 2nd gear wheel 6 - 3rd gear wheel 7 - 3rd/4th gear synchronizer clutch 8 - 4th gear wheel 9 - Output shaft 1st/4th gear 10 - Input shaft 11 - Output shaft 5th/6th/reverse gear 12 - 6th gear wheel 13 - 5th/6th gear synchronizer clutch 14 - 5th gear wheel 15 - Reverse gear synchronizer clutch 16 - Reverse gear wheel 17 - Output pinion – 5th/6th/reverse gear output shaft 18 - Clutch housing Construction features on the differential side All gears have helical teeth and are permanently engaged. 5th and 6th gear and reverse gear have single synchronizers. 3rd and 4th gear have double synchronizers; 1st and 2nd gear have triple synchronizers. Construction features on the input shaft side.   Item Part Number Description 1 - Output shaft 5th/6th/reverse gear 2 - Input shaft 3 - Output shaft 1st/4th gear 4 - 3rd/4th gear synchronizer clutch selector fork 5 - 1st/2nd gear synchronizer clutch selector fork 6 - Clutch housing 7 - 1st gear 8 - 2nd gear 9 - 5th gear 10 - Reverse gear synchronizer clutch selector fork 11 - 3rd gear 12 - 5th/6th gear synchronizer clutch selector fork 13 - 4th/6th gear gearwheel All driving gear wheels of the transmission are located on the input shaft. The input shaft is a solid shaft and runs on one ball bearing and one roller bearing. Because of this mounting the input shafts runs without preload and therefore needs no adjusting shims. The input shaft seal nearest the clutch is pressed into the clutch housing. Input shaft   Item Part Number Description 1 - Input shaft bearing (inner race shown) 2 - 1st gear 3 - 2nd gear 4 - 5th gear 5 - 3rd gear 6 - Input shaft ball bearing holder 7 - Bearing retaining bolt 8 - 4th/6th gear gearwheel Input shaft The gear wheels for 1st and 2nd gear are an integral part of the input shaft. The gearwheels for 3rd and 5th gears and the gearwheel for 4th/6th gear are pressed on. Because of the high force used to press on the components, the gear wheels cannot be pressed off in service. A faulty input shaft can only be replaced as a complete unit. Defective bearings can be pressed off and changed. Output shaft 1st/4th gear The 1st/4th gear output shaft runs on tapered roller bearings. This bearing arrangement requires the shaft to be preloaded. Please refer to the service literature for further information on how to measure the pre-load. The output pinion of the 1st/4th gear output shaft is an integral part of the shaft. The synchroniser assemblies of the 1st/2nd and the 3rd/4th gears are located on the output shaft. The 1st to 4th gear output shaft is a hollow shaft; the oil is supplied to the internal oilways via oil funnels. Internal oilways provide lubrication to the needle roller bearings and the synchroniser assemblies.   Item Part Number Description 1 - Transmission housing taper roller bearing 2 - 4th gear wheel 3 - 4th gear needle bearing 4 - Inner synchronizer ring 5 - 4th gear synchronizer cone 6 - Outer synchronizer ring (4th gear) 7 - Snap ring 8 - 3rd/4th gear synchronizer 9 - Outer synchronizer ring (3rd gear) 10 - 3rd gear synchronizer cone 11 - Inner synchronizer ring 12 - 3rd gear wheel 13 - 3rd gear needle bearing 14 - Stop disc unit 15 - 2nd gear wheel 16 - 2nd gear needle bearing 17 - Inner synchronizer ring 18 - 2nd gear synchronizer cone 19 - Outer synchronizer ring (2nd gear) 20 - Snap ring 21 - 1st/2nd gear synchronizer 22 - Outer synchronizer ring (1st gear) 23 - 1st gear synchronizer cone 24 - Inner synchronizer ring 25 - 1st gear wheel 26 - 1st gear needle bearing 27 - Output shaft 1st/4th gear 28 - Clutch housing taper roller bearing 29 - Bearing retaining bolt (left-hand thread) Output shaft 5th/6th/reverse gear The 5th/6th/reverse gear output shaft runs on tapered roller bearings. This bearing arrangement requires the shaft to be preloaded. Please refer to the service literature for further information on how to measure the pre-load. The output pinion is an integral part of the shaft. The 5th/6th and reverse gear synchronizer assemblies are located on the shaft. The 5th/6th/reverse gear output shaft is a hollow shaft; the oil is supplied to the internal oilways via oil funnels. Internal oilways provide lubrication to the needle roller bearings and the synchroniser assemblies.   Item Part Number Description 1 - Transmission housing taper roller bearing 2 - 6th gear needle bearing 3 - 6th gear wheel 4 - 6th gear synchronizer ring 5 - Snap ring 6 - 5th/6th gear synchronizer 7 - Synchronizer ring (5th gear) 8 - Stop disc unit 9 - 5th gear needle bearing 10 - 5th gear wheel 11 - Snap ring 12 - Clutch housing taper roller bearing 13 - Output shaft 5th/6th/reverse gear 14 - Reverse gear wheel 15 - Needle roller bearings 16 - Reverse gear synchronizer ring 17 - Reverse gear synchronizer 18 - Bearing retaining bolt (left-hand thread) Oil thrower An oil thrower is installed on each of the two output shafts, at the clutch end.   Item Part Number Description - Oil thrower The oil thrower must always be renewed. If the oil throwers are damaged, this could lead to a loss of transmission fluid pressure in the output shaft and therefore to a loss of lubrication. Synchroniser assembly   Item Part Number Description 1 - Sliding block assembly 2 - Synchroniser hub 3 - Sliding collar The (MMT6) synchroniser assemblies have been reworked for the 6-speed manual transmission. The detent balls, springs and sliding blocks form one unit. This arrangement makes it easier to service the synchroniser assembly. Differential Because the Vehicle Speed Sensor (VSS) is discontinued, so is the sender wheel. The ABS wheel speed sensors send the current wheel speed to the powertrain control module (PCM). The differential has taper roller bearings. This bearing arrangement requires the shaft to be preloaded. Please refer to the service literature for further information on how to measure the pre-load.   Item Part Number Description 1 - Transmission housing taper roller bearing 2 - Differential 3 - Clutch housing taper roller bearing 4 - Crown wheel bolts 5 - Crown wheel Power transmission in the individual gears The following diagrams show a schematic representation of the power flow. Power is transmitted via the non-positive gear pair to the output pinion of the output shaft(s) and thus to the differential ring gear. NOTE: The three shafts are shown away from their real positions for clarity. Power transmission route in 1st gear The 1st gear wheel is positively connected to the 1st to 4th gear output shaft by the 1st/2nd gear synchroniser assembly. Power transmission route in second gear The 2nd gear wheel is positively connected to the 1st to 4th gear output shaft by the 1st/2nd gear synchroniser assembly. Power transmission route in 3rd gear The 3rd gear wheel is positively connected to the 1st to 4th gear output shaft by the 3rd/4th gear synchroniser assembly. Power transmission route in 4th gear The 4th gear wheel is positively connected to the 1st to 4th gear output shaft by the 3rd/4th gear synchroniser assembly. Power transmission route in 5th gear The 5th gear wheel is positively connected to the 5th/6th/reverse gear output shaft by the 5th/6th gear synchroniser assembly. Power transmission route in 6th gear The gear wheel of the 4th/6th gear drives not only the gear wheel of the 4th gear but also of the 6th gear. The 6th gear wheel is positively connected to the 5th/6th/reverse gear output shaft by the 5th/6th gear synchroniser assembly. Power transmission route in reverse gear The reverse gear idler is welded to the 1st gear wheel. It is constantly engaged with the reverse gear wheel (shown separated for clarity). The reverse gear wheel is positively connected to the 5th/6th/reverse gear output shaft by the reverse gear synchroniser assembly. Internal shift mechanism   Item Part Number Description 1 - Counterbalance 2 - Reverse gear switch 3 - Selector shaft 4 - Selector gate Internal shift mechanism The internal shift mechanism has been newly developed for this transmission. The reverse gear switch is located on the housing cover of the internal shift mechanism. The counterbalance improves the smoothness of the gear shifting. Due to its mass, the synchronization shift resistances that can be felt during shifting are reduced. The gear shifting process becomes smoother. The internal shift mechanism can only be changed as a complete unit in service.