<strong>Manual</strong> <strong>Gearbox</strong> - 4 <strong>Synchro</strong> <strong>Internal</strong> <strong>Components</strong> No. Part No. Description Qty. Remarks No. Part No. Description Qty. Remarks The 4 <strong>Synchro</strong> <strong>Gearbox</strong> 1968 On Fortunately 4 synchro gearboxes are much easier to identify and classify than their 3 synchro predecessors (parts availability is considerably better, too, but not brilliant in some areas). The two main changes are the modification of gear shafts and several of the bearings in 1979, and A Plus gears. A Plus gears were pro gressively introduced, the bulk of models changing over around 1982. The y have a sharper tooth angle and different pitch making them quieter than the earlier gears, with which they are not interchangeable. A Plus gears may be identified by the presence of a circumferential groo ve in the centre of the teeth, plus flush machining on both sides of the final drive pinion. The following summaries help with identification and give you points to watch for when ordering par ts: DAM3092 SHAFT, 1st motion, 17 teeth 1 1979-82; not 1275 models. DAM3167 SHAFT, 1st motion, 18 teeth 1 1979-80; 1275 models. DAM4930 SHAFT, 1st motion, 17 teeth, A Plus type 1 1982 on; not 1990-96, 1275 (France). DAM6242 SHAFT, 1st motion, 16 teeth, A Plus type 1 1990-96, 1275 (France). 16 22G2033 RING, baulk 1 17 CHM172 BEARING, 1st/3rd motion shafts, 9/16” i.d.1 For 22G1093/22G1371 1st motion shafts. 13H9513 BEARING, 1st/3rd motion shafts, 11/16” i.d.1 For all other 1st motion shafts . 18 ADU7619 BEARING, 1st motion shaft 1 In gearbox case. 19 22G850 CIRCLIP, bearing retaining 1 0.094-0.096" (2.39-2.44mm) 22G851 CIRCLIP, bearing retaining 1 0.097-0.099" (2.46-2.51mm) For the 1st motion shaft bearing supporting the nose of the shaft in the flywheel housing, please see the ‘Flywheel Housing and Clutch Cover’ section of the Somerford Mini Catalogue. 1968-73 Saloon and Estate, 1968-75 Van and Pick Up Pre-A Plus gears. Direct/remote gearchange type reverse gear and mainshaft bearing retainer (four screw fitting). 9/16" dia. nose on 3rd motion shaft, two step layshaft, laygear takes two large bearings and one small bearing. Different ratios for 1275 models. 1973-79 Saloon and Estate, 1975-79 Van and Pick Up Pre-A Plus gears. Rod gearchange type reverse gear and mainshaft bearing retainer (4 screw fitting). 9/16" dia. nose on 3rd motion shaft, two step la yshaft,laygear takes two large bearings and one small bearing. Different ratios for 1275 models . 1979-82 Pre-A Plus gears (except for final drive pinion on 3.444:1 ratio models, which became A Plus in 1979). Rod gearchange type reverse gear and mainshaft bearing retainer (4 screw fitting). 11/16" dia. nose on 3rd motion shaft, three step layshaft, laygear takes one large and one small bearing. Idler and 1st motion shaft drive gear ratios revised, idler gear bearings in gearbox case revised (diameter change). Different ratios for 1275 models. 3rd Motion Shaft 20 22G833 SHAFT, 3rd motion, 9/16" nose dia. 1 1968-79. DAM7484 SHAFT, 3rd motion, 11/16" nose dia. 1 1979 on. 21 AAU1365 BEARING, 3rd motion shaft 1 22 ADU4992 RING, spring, bearing retaining 1 23 22A522 RETAINER, 3rd motion shaft bearing, 1 1968-73, Saloons and Estates; 4 screw fixing, direct/remote change type 1968-75, Vans and Pick Ups. DAM1756 RETAINER, 3rd motion shaft bearing, 1 1973-84, Saloons and Estates; 4 screw fixing, rod change type 1976-84, Vans and Pick Ups. 24 DAM5996 RETAINER, 3rd motion shaft bearing, 1 1984 on. 3 screw fixing, rod change type 25 SH505071 SCREW, retainer to gearbox case 4/3 Qty. 4 for 22A522/DAM1756 retainers . 26 DAM2377 LOCK TAB, screw 2/1 Qty. 2 for 22A522/DAM1756 retainers . 27 DAM6047 LOCK TAB, screw 1 For DAM5996 retainer. 28 2A3714 SHIM, retainer A/R 0.003" (0.076mm) 2A3715 SHIM, retainer A/R 0.010" (0.254mm) 1982 on A Plus gears. Rod gearchange type reverse gear and mainshaft bearing retainer (4 screw fitting reducing to 3 screw fitting in 1984). 11/16" dia. nose on 3rd motion shaft, three step layshaft, laygear takes one large and one small bearing. Different ratios for French 1275 models in the 1990s. Close ratio and straight cut close ratio gear sets are available for 4 synchro pre-A Plus and A Plus gearboxes, as special orders; please contact us for details. Similarly, contact us if you already have Special Tuning helical close ratio or straight cut close ratio gears and you require replacement parts. Reverse Idler Gear 1 22G1034 REVERSE IDLER, 17/18 teeth, 1 1968-73, Saloons and Estates; direct/remote gearchange type 1968-75, Vans and Pick Ups. 22G1832 REVERSE IDLER, 17/18 teeth, 1 1973-79, Saloons and Estates; rod gearchange type 1976-79, Vans and Pick Ups. TUB10020 REVERSE IDLER, 17/18 teeth, 1 1979 on. rod gearchange type 2 TUJ10001 BUSH, reverse idler 1 3 DAM8038 SHAFT, reverse idler 1 Laygear 4 22G927 LAYGEAR, 15/20/25/29 teeth 1 1968-79; 2 step layshaft, not 1275. 22G1040 LAYGEAR, 15/20/25/29 teeth 1 1968-79; 2 step layshaft, 1275. 5 DAM3169 LAYGEAR, 15/20/25/29 teeth 1 1979-82; 3 step layshaft, not 1275. DAM3168 LAYGEAR, 15/20/25/29 teeth 1 1979-80; 3 step layshaft, 1275. DAM4931 LAYGEAR, 15/21/26/30 teeth, A Plus type 1 1982 on; 3 step layshaft, not 1990-96, 1275 France . DAM6238 LAYGEAR, 15/21/27/31 teeth, A Plus type 1 1990-96, 3 step layshaft, 1275 France. 6 22G931 LAYSHAFT, two step type 1 Fit to 22G927 and 22G1040 laygears. 7 DAM3187 LAYSHAFT, three step type 1 Fit to all other laygears . 8 2A3581 PLATE, locating reverse idler shaft/layshaft 1 9 CHM141 BEARING, needle roller, laygear, large 2/1 Qty. 2 in 22G927/22G1040 gears only. 10 88G396 BEARING, needle roller, laygear, small 1 Fit to 22G927 and 22G1040 gears only. 11 13H9513 BEARING, needle roller, laygear, small 1 Fit to all other laygears . 12 22G856 WASHER, thrust, small, 0.123-0.124" 1 Fit to 22G927 and 22G1040 laygears. (3.12-3.14mm) 22G857 WASHER, thrust, small, 0.125-0.126" 1 Fit to 22G927 and 22G1040 laygears. (3.17-3.20mm) 22G858 WASHER, thrust, small, 0.127-0.128" 1 Fit to 22G927 and 22G1040 laygears. (3.22-3.25mm) 22G859 WASHER, thrust, small, 0.130-0.131" 1 Fit to 22G927 and 22G1040 laygears. (3.30-3.32mm) 13 DAM3180 WASHER, thrust, small, 0.121-0.123" 1 Fit to DAM3169, DAM3168, DAM4931 (3.07-3.12mm) and DAM6238 laygears . DAM3181 WASHER, thrust, small, 0.124-0.126" 1 Fit to DAM3169, DAM3168, DAM4931 (3.15-3.20mm) and DAM6238 laygears . DAM3182 WASHER, thrust, small, 0.127-0.129" 1 Fit to DAM3169, DAM3168, DAM4931 (3.22-3.27mm) and DAM6238 laygears . DAM3183 WASHER, thrust, small, 0.130-0.132" 1 Fit to DAM3169, DAM3168, DAM4931 (3.30-3.35mm) and DAM6238 laygears . 14 22G860 WASHER, thrust, large 1 1st Motion Shaft 15 22G1093 SHAFT, 1st motion, 17 teeth 1 1968-79; not 1275 models. 22G1371 SHAFT, 1st motion, 18 teeth 1 1968-79; 1275 models. 1st Gear 29 22G1096 GEAR, 1st speed, 31 teeth 1 30 22G2033 RING, baulk 1 31 AAU1815 BEARING, needle roller, 1st speed gear 1 32 22G837 JOURNAL, 1st speed gear 1 1st/2nd <strong>Synchro</strong>niser 33 DAM7455 GEAR ASS’Y, 1st/2nd synchroniser 1 34 BLS107 BALL, synchroniser 3 35 22G2262 SPRING, synchroniser 3 2nd Gear 36 22G1094 GEAR, 2nd speed, 26 teeth 1 1968-82. DAM4932 GEAR, 2nd speed, 26 teeth, A Plus type 1 1982 on; not 1990-96, 1275 (France). DAM6240 GEAR, 2nd speed, 25 teeth, A Plus type 1 1990-96, 1275 (France). 37 22G2033 RING, baulk 1 38 AAU1816 BEARING, needle roller, 2nd speed gear 1 39 22G839 WASHER, thrust, 2nd speed gear 1 40 22G843 PEG, 2nd speed gear 2 41 22G154 SPRING, 2nd speed gear 1 3rd Gear 42 22G1095 GEAR, 3rd speed, 21 teeth 1 1968-82. DAM4933 GEAR, 3rd speed, 21 teeth, A Plus type 1 1982 on; not 1990-96, 1275 (France). DAM6241 GEAR, 3rd speed, 20 teeth, A Plus type 1 1990-96, 1275 (France). 43 22G2033 RING, baulk 1 44 AAU1816 BEARING, needle roller, 3rd speed gear 1 45 22G947 WASHER, thrust, 3rd speed gear 1 46 22G843 PEG, 3rd speed gear 1 47 22G154 SPRING, 3rd speed gear 1 3rd/4th <strong>Synchro</strong>niser 48 DAM7456 GEAR ASS’Y, 3rd/4th synchroniser 1 49 BLS107 BALL, synchroniser 3 50 22G2262 SPRING, synchroniser 3 Final Drive Pinion 51 22G99 PINION, 15 teeth, 4.333:1 ratio 1 With 65 tooth 22G443 final drive gear. 22G99 PINION, 15 teeth, 4.267:1 ratio 1 With 64 tooth 22G370 final drive gear. 22G99 PINION, 15 teeth, 4.133:1 ratio 1 With 62 tooth 22G101 final drive gear. 22G338 PINION, 16 teeth, 3.938:1 ratio 1 With 63 tooth 22G340 final drive gear. 22A399 PINION, 17 teeth, 3.765:1 ratio 1 With 64 tooth 22A401 final drive gear. 22A399 PINION, 17 teeth, 3.647:1 ratio 1 With 62 tooth 22G940 final drive gear. 22A413 PINION, 18 teeth, 3.444:1 ratio 1 With 62 tooth 22A411 final drive gear. DAM3647 PINION, 15 teeth, A Plus, 4.333:1 ratio 1 With 65 tooth DAM3645 final drive gear. DAM3218 PINION, 16 teeth, A Plus, 3.938:1 ratio 1 With 63 tooth DAM3216 final drive gear. DAM4131 PINION, 17 teeth, A Plus, 3.765:1 ratio 1 With 64 tooth DAM4779 final drive gear. DAM4131 PINION, 17 teeth, A Plus, 3.647:1 ratio 1 With 62 tooth DAM4162 final drive gear. DAM2679 PINION, 18 teeth, A Plus, 3.444:1 ratio 1 With 62 tooth DAM2677 final drive gear. DAM2808 PINION, 19 teeth, A Plus, 3.211:1 ratio 1 With 61 tooth DAM2806 final drive gear. DAM2808 PINION, 19 teeth, A Plus, 3.105:1 ratio 1 With 59 tooth DAM6327 final drive gear. DAM5927 PINION, 20 teeth, A Plus, 2.950:1 ratio 1 With 59 tooth DAM5925 final drive gear. TCC10001 PINION, 21 teeth, A Plus, 2.762:1 ratio 1 With 58 tooth TCB10004 final drive gear. 52 DAM7485 NUT, pinion retaining 1 53 DAM6140 LOCK TAB, pinion nut 1 Tel. 01249 721421 Fax. 01249 721316 www.somerford-mini.co.uk 17
<strong>Manual</strong> <strong>Gearbox</strong> - Selectors and Speedometer Drives © Copyright Somerford Mini Limited 18 Tel. 01249 721421 Fax. 01249 721316 www.somerford-mini.co.uk
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