4 Synchro Internal Gearbox |
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1968 On |
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Fortunately for the majority of our customers, 4 synchro gearboxes are much easier to identify and classify than their 3 synchro predecessors (parts |
availability is considerably better, too, but not brilliant sometimes). The two main change points are 1979, when the gear shafts and several of the |
bearings were modified, and 1982 - approximately - when A Plus gears were introduced. |
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A Plus gears were introduced on the Mini round about 1982 (at different times on different models...), and have a sharper tooth angle and different pitch |
making them quieter than, but definitely not interchangeable with, the earlier gears. Looking in the gearbox, A Plus gears can be identified by the |
presence of a circumferential groove in the centre of the teeth, and the final drive pinion on the gearbox mainshaft is machined flush on both sides. |
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The following summaries should help with the identification of your gearbox and give you points to watch out for when ordering parts: |
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1968-73 Saloon and Estate, 1968-75 Van and Pick Up |
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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. |
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1973-79 Saloon and Estate, 1975-79 Van and Pick Up |
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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 |
layshaft, laygear takes two large bearings and one small bearing. Different ratios for 1275 models. |
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1979-82 |
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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. |
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1982 on |
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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. |
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Close ratio and straight cut close ratio gear sets are available for 4 synchro pre-A Plus and A Plus gearboxes, as a special order. Please contact |
us for details. Similarly, please contact us if you already have factory-optional helical close ratio or straight cut close ratio gears in your gearbox and |
you require replacement parts. |
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Reverse Idler Gear |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
1 |
22G1034 |
REVERSE IDLER, 17/18 teeth, direct/remote gearchange type |
1 |
1968-73, Saloons and Estates; 1968-75, Vans and Pick Ups. |
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22G1832 |
REVERSE IDLER, 17/18 teeth, rod gearchange type |
1 |
1973-79, Saloons and Estates; 1976-79, Vans and Pick Ups. |
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TUB10020 |
REVERSE IDLER, 17/18 teeth, rod gearchange type |
1 |
1979 on. |
2 |
TUJ10001 |
BUSH, reverse idler |
1 |
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3 |
DAM8038 |
SHAFT, reverse idler |
1 |
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Laygear |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
4 |
22G927 |
LAYGEAR, 15/20/25/29 teeth, for two step layshaft |
1 |
1968-79; not 1275 models. |
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22G1040 |
LAYGEAR, 15/20/25/29 teeth, for two step layshaft |
1 |
1968-79; 1275 models. |
5 |
DAM3169 |
LAYGEAR, 15/20/25/29 teeth, for three step layshaft |
1 |
1979-82; not 1275 models. |
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DAM3168 |
LAYGEAR, 15/20/25/29 teeth, for three step layshaft |
1 |
1979-80; 1275 models. |
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DAM4931 |
LAYGEAR, 15/21/26/30 teeth, A Plus type, for three step layshaft |
1 |
1982 on; not 1990-96, 1275 (France). |
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DAM6238 |
LAYGEAR, 15/21/27/31 teeth, A Plus type, for three step layshaft |
1 |
1990-96, 1275 (France). |
6 |
22G931 |
LAYSHAFT, two step type |
1 |
Fit to 22G927 and 22G1040 laygears. |
7 |
DAM3187 |
LAYSHAFT, three step type |
1 |
Fit to DAM3169, DAM3168, DAM4931 and DAM6238 laygears. |
8 |
2A3581 |
PLATE, locating reverse idler shaft and layshaft |
1 |
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9 |
CHM141 |
BEARING, needle roller, laygear, large |
2/1 |
Qty. 2 fitted to 22G927 and 22G1040 laygears only. |
10 |
88G396 |
BEARING, needle roller, laygear, small |
1 |
Fit to 22G927 and 22G1040 laygears. |
11 |
13H9513 |
BEARING, needle roller, laygear, small |
1 |
Fit to DAM3169, DAM3168, DAM4931 and DAM6238 laygears. |
12 |
22G856 |
WASHER, thrust, small, 0.123-0.124" (3.12-3.14mm) |
1 |
Fit to 22G927 and 22G1040 laygears. |
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22G857 |
WASHER, thrust, small, 0.125-0.126" (3.17-3.20mm) |
1 |
Fit to 22G927 and 22G1040 laygears. |
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22G858 |
WASHER, thrust, small, 0.127-0.128" (3.22-3.25mm) |
1 |
Fit to 22G927 and 22G1040 laygears. |
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22G859 |
WASHER, thrust, small, 0.130-0.131" (3.30-3.32mm) |
1 |
Fit to 22G927 and 22G1040 laygears. |
13 |
DAM3180 |
WASHER, thrust, small, 0.121-0.123" (3.07-3.12mm) |
1 |
Fit to DAM3169, DAM3168, DAM4931 and DAM6238 laygears. |
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DAM3181 |
WASHER, thrust, small, 0.124-0.126" (3.15-3.20mm) |
1 |
Fit to DAM3169, DAM3168, DAM4931 and DAM6238 laygears. |
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DAM3182 |
WASHER, thrust, small, 0.127-0.129" (3.22-3.27mm) |
1 |
Fit to DAM3169, DAM3168, DAM4931 and DAM6238 laygears. |
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DAM3183 |
WASHER, thrust, small, 0.130-0.132" (3.30-3.35mm) |
1 |
Fit to DAM3169, DAM3168, DAM4931 and DAM6238 laygears. |
14 |
22G860 |
WASHER, thrust, large |
1 |
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1st Motion Shaft |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
15 |
22G1093 |
SHAFT, 1st motion, 17 teeth |
1 |
1968-79; not 1275 models. |
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22G1371 |
SHAFT, 1st motion, 18 teeth |
1 |
1968-79; 1275 models. |
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DAM3092 |
SHAFT, 1st motion, 17 teeth |
1 |
1979-82; not 1275 models. |
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DAM3167 |
SHAFT, 1st motion, 18 teeth |
1 |
1979-80; 1275 models. |
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DAM4930 |
SHAFT, 1st motion, 17 teeth, A Plus type |
1 |
1982 on; not 1990-96, 1275 (France). |
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DAM6242 |
SHAFT, 1st motion, 16 teeth, A Plus type |
1 |
1990-96, 1275 (France). |
16 |
22G2033 |
RING, baulk |
1 |
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17 |
CHM172 |
BEARING, 1st to 3rd motion shaft, 9/16" int. dia. |
1 |
Fit to 22G1093 and 22G1371 1st motion shafts. |
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13H9513 |
BEARING, 1st to 3rd motion shaft, 11/16" int. dia. |
1 |
Fit to DAM3092, DAM3167, DAM4930 and DAM6242 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) |
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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. |
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3rd Motion Shaft |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
20 |
22G833 |
SHAFT, 3rd motion, 9/16" nose dia. |
1 |
1968-79. |
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DAM7484 |
SHAFT, 3rd motion, 11/16" nose dia. |
1 |
1979 on. |
21 |
AAU1365 |
BEARING, 3rd motion shaft |
1 |
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22 |
ADU4992 |
RING, spring, bearing retaining |
1 |
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23 |
22A522 |
RETAINER, 3rd motion shaft bearing, 4 screw fixing, direct/remote gearchange type |
1 |
1968-73, Saloons and Estates; 1968-75, Vans and Pick Ups. |
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DAM1756 |
RETAINER, 3rd motion shaft bearing, 4 screw fixing, rod gearchange type |
1 |
1973-84, Saloons and Estates; 1976-84, Vans and Pick Ups. |
24 |
DAM5996 |
RETAINER, 3rd motion shaft bearing, 3 screw fixing, rod gearchange type |
1 |
1984 on. |
25 |
SH505071 |
SCREW, coarse thread, retainer to gearbox case |
4/3 |
Qty. 4 fitted to 22A522 and DAM1756 retainers only. |
26 |
DAM2377 |
LOCK TAB, screw |
2/1 |
Qty. 2 fitted to 22A522 and DAM1756 retainers only. |
27 |
DAM6047 |
LOCK TAB, screw |
1 |
Fitted to DAM5996 retainer. |
28 |
2A3714 |
SHIM, retainer |
A/R |
0.003" (0.076mm) |
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2A3715 |
SHIM, retainer |
A/R |
0.010" (0.254mm) |
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1st Gear |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
29 |
22G1096 |
GEAR, 1st speed, 31 teeth |
1 |
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30 |
22G2033 |
RING, baulk |
1 |
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31 |
AAU1815 |
BEARING, needle roller, 1st speed gear |
1 |
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32 |
22G837 |
JOURNAL, 1st speed gear |
1 |
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1st/2nd Synchroniser |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
33 |
DAM7455 |
GEAR ASS'Y, 1st/2nd synchroniser |
1 |
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34 |
BLS107 |
BALL, synchroniser |
3 |
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35 |
22G2262 |
SPRING, synchroniser |
3 |
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2nd Gear |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
36 |
22G1094 |
GEAR, 2nd speed, 26 teeth |
1 |
1968-82. |
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DAM4932 |
GEAR, 2nd speed, 26 teeth, A Plus type |
1 |
1982 on; not 1990-96, 1275 (France). |
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DAM6240 |
GEAR, 2nd speed, 25 teeth, A Plus type |
1 |
1990-96, 1275 (France). |
37 |
22G2033 |
RING, baulk |
1 |
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38 |
AAU1816 |
BEARING, needle roller, 2nd speed gear |
1 |
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39 |
22G839 |
WASHER, thrust, 2nd speed gear |
1 |
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40 |
22G843 |
PEG, 2nd speed gear |
2 |
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41 |
22G154 |
SPRING, 2nd speed gear |
1 |
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3rd Gear |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
42 |
22G1095 |
GEAR, 3rd speed, 21 teeth |
1 |
1968-82. |
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DAM4933 |
GEAR, 3rd speed, 21 teeth, A Plus type |
1 |
1982 on; not 1990-96, 1275 (France). |
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DAM6241 |
GEAR, 3rd speed, 20 teeth, A Plus type |
1 |
1990-96, 1275 (France). |
43 |
22G2033 |
RING, baulk |
1 |
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44 |
AAU1816 |
BEARING, needle roller, 3rd speed gear |
1 |
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45 |
22G947 |
WASHER, thrust, 3rd speed gear |
1 |
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46 |
22G843 |
PEG, 3rd speed gear |
1 |
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47 |
22G154 |
SPRING, 3rd speed gear |
1 |
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3rd/4th Synchroniser |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
48 |
DAM7456 |
GEAR ASS'Y, 3rd/4th synchroniser |
1 |
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49 |
BLS107 |
BALL, synchroniser |
3 |
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50 |
22G2262 |
SPRING, synchroniser |
3 |
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Final Drive Pinion |
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Ill. No. |
Part No. |
Description |
Qty. Rqd. |
Remarks |
51 |
22G99 |
PINION, final drive, 15 teeth |
1 |
4.333:1 ratio (with 65 tooth 22G443 final drive gear). |
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22G99 |
PINION, final drive, 15 teeth |
1 |
4.267:1 ratio (with 64 tooth 22G370 final drive gear). |
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22G99 |
PINION, final drive, 15 teeth |
1 |
4.133:1 ratio (with 62 tooth 22G101 final drive gear). |
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22G338 |
PINION, final drive, 16 teeth |
1 |
3.938:1 ratio (with 63 tooth 22G340 final drive gear). |
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22A399 |
PINION, final drive, 17 teeth |
1 |
3.765:1 ratio (with 64 tooth 22A401 final drive gear). |
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22A399 |
PINION, final drive, 17 teeth |
1 |
3.647:1 ratio (with 62 tooth 22G940 final drive gear). |
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22A413 |
PINION, final drive, 18 teeth |
1 |
3.444:1 ratio (with 62 tooth 22A411 final drive gear). |
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DAM3647 |
PINION, final drive, 15 teeth, A Plus type |
1 |
4.333:1 ratio (with 65 tooth DAM3645 final drive gear). |
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DAM3218 |
PINION, final drive, 16 teeth, A Plus type |
1 |
3.938:1 ratio (with 63 tooth DAM3216 final drive gear). |
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DAM4131 |
PINION, final drive, 17 teeth, A Plus type |
1 |
3.765:1 ratio (with 64 tooth DAM4779 final drive gear). |
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DAM4131 |
PINION, final drive, 17 teeth, A Plus type |
1 |
3.647:1 ratio (with 62 tooth DAM4162 final drive gear). |
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DAM2679 |
PINION, final drive, 18 teeth, A Plus type |
1 |
3.444:1 ratio (with 62 tooth DAM2677 final drive gear). |
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DAM2808 |
PINION, final drive, 19 teeth, A Plus type |
1 |
3.211:1 ratio (with 61 tooth DAM2806 final drive gear). |
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DAM2808 |
PINION, final drive, 19 teeth, A Plus type |
1 |
3.105:1 ratio (with 59 tooth DAM6327 final drive gear). |
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DAM5927 |
PINION, final drive, 20 teeth, A Plus type |
1 |
2.950:1 ratio (with 59 tooth DAM5925 final drive gear). |
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TCC10001 |
PINION, final drive, 21 teeth, A Plus type |
1 |
2.762:1 ratio (with 58 tooth TCB10004 final drive gear). |
52 |
22G48 |
NUT, pinion retaining |
1 |
1968-82. |
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DAM7485 |
NUT, pinion retaining, A Plus type |
1 |
1982 on. |
53 |
DAM6140 |
LOCK TAB, pinion nut |
1 |
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