Manual gearbox - primary, idler and 1st motion shaft drive gears

Primary (Output), Idler and 1st Motion Shaft Drive (Input) Gears
Several different combinations of primary gear and bushes were used on the earliest Mini power units built between 1959 and 1963, following the abject
failure of the first, the so-called 'D.U.' bush and oil seal design (which allowed engine oil seepage onto the clutch all too frequently). As an interim measure,
a revised oil-fed bush system was fitted - in most cases when the car came in for the inevitable clutch replacement - and after a couple of false starts the
'Deva' dry-lubricated bush became the standard fitment. Each system necessitated a different engine crankshaft and flywheel, as well as the primary
gear and bushes. Extra care must be taken to select matching components for these early designs.

From 1963 onwards, crankshaft, flywheel, primary gear and bush combinations settled down into two designs, depending on the crankshaft tail dimensions:
one combination for 848, 998 and 1098 engines and the other for 1071, 1275 and 970 engines. This continued right the way through to 1979 when 'A Plus'
gears were introduced, which saw production out through to 2000.

Primary gears are supplied with their bushes fitted, as ready-to-use assemblies. However, if you intend to fit replacement bushes in a primary gear, the
bushes must be machined after fitment to ensure alignment with each other.

By contrast, the idler and 1st motion shaft drive gears saw far fewer changes, being limited to 3 synchro gearbox (1959-68), pre-A Plus 4 synchro gearbox
(1968-79) and A Plus (1979 on). Of these, pre-A Plus 4 synchro gears may be used on 3 synchro gearboxes if certain other components are fitted at the
same time. However, pre-A Plus and A Plus gears cannot be mixed and matched together.

Bearings (and their retaining circlips) for the idler and drive gears may be found in the 'Flywheel Housing and Clutch Cover' and 'Manual Gearbox - External'
sections of this catalogue. Primary, idler and drive gears for automatic Minis may be found in the 'Automatic Transmission - Torque Converter and Housing'
section.

Primary Gears
1959-62, Oil-fed Bush Type 848 Engines
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
1	22A79	PRIMARY GEAR ASS'Y, with bushes, 24 teeth	1
2	22A81	BUSH, primary gear, front	1
3	22A82	BUSH, primary gear, rear	1

1961-62, Oil-fed Bush Type 997 Engines
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
4	12A380	PRIMARY GEAR ASS'Y, with bushes, 24 teeth	1
5	12A386	BUSH, primary gear, front	1
6	12A385	BUSH, primary gear, rear	1

1962-63, Deva Bush Type 848 Engines With 1 3/8" dia. Flywheel Machining
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
7	22A520	PRIMARY GEAR ASS'Y, with bushes, 24 teeth	1
8	22A447	BUSH, primary gear, front	1
9	22A448	BUSH, primary gear, rear	1

1962-63, Deva Bush Type 997 Engines With 1 3/8" dia. Flywheel Machining
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
10	22G106	PRIMARY GEAR ASS'Y, with bushes, 24 teeth	1
11	22G108	BUSH, primary gear, front	1
12	22G109	BUSH, primary gear, rear	1

1963, Deva Bush Type 997 and 998 Engines With 1 1/2" dia. Flywheel Machining
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
13	22A551	PRIMARY GEAR ASS'Y, with bushes, 24 teeth	1
14	22A553	BUSH, primary gear, front	1
15	22G109	BUSH, primary gear, rear	1

1963-92, Deva Bush Type 848, 998 and 1098 Engines With 1 1/2" dia. Flywheel Machining
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
16	22A1493	PRIMARY GEAR ASS'Y, with bushes, 24 teeth	1	1963-79.
	DAM8888	PRIMARY GEAR ASS'Y, with bushes, 29 teeth	1	1979-92; A Plus.
17	DAM2821	DUST SHIELD	1	1979-92; A Plus.
18	DAM8887	BUSH, primary gear, front	1
19	22G109	BUSH, primary gear, rear	1

1963 On, Deva Bush Type 1071, 1275 and 970 Engines With 1 1/2" dia. Flywheel Machining
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
20	22G1053	PRIMARY GEAR ASS'Y, with bushes, 24 teeth	1	1963-79.
	DAM8890	PRIMARY GEAR ASS'Y, with bushes, 29 teeth	1	1979 on; A Plus. Not France, 1990-96.
	DAM9373	PRIMARY GEAR ASS'Y, with bushes, 30 teeth	1	A Plus. France, 1990-96.
21	DAM2821	DUST SHIELD	1	1979 on; A Plus.
22	DAM8889	BUSH, primary gear, front	1
23	22G109	BUSH, primary gear, rear	1

Primary Gear Front Thrust Washers
848, 997, 998 and 1098 Engines, Except 848 Engines 1962-63
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
24	22A321	WASHER, thrust, primary gear, front	1	0.110-0.112" (2.79-2.84mm).
	22A322	WASHER, thrust, primary gear, front	1	0.112-0.114" (2.84-2.89mm).
	22A323	WASHER, thrust, primary gear, front	1	0.114-0.116" (2.89-2.94mm).
	22A324	WASHER, thrust, primary gear, front	1	0.116-0.118" (2.94-2.99mm).
	22A450	WASHER, thrust, primary gear, front	1	0.118-0.120" (2.99-3.04mm).

848 Engines 1962-63
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
25	22A295	WASHER, thrust, primary gear, front	1	0.123-0.125" (3.12-3.17mm).
	22A83	WASHER, thrust, primary gear, front	1	0.125-0.127" (3.17-3.22mm).
	22A238	WASHER, thrust, primary gear, front	1	0.127-0.129" (3.22-3.28mm).
	22A239	WASHER, thrust, primary gear, front	1	0.129-0.131" (3.28-3.32mm).

1071, 1275 and 970 Engines
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
26	DAM6490	WASHER, thrust, primary gear, front	1	0.112-0.114" (2.84-2.89mm).
	DAM6486	WASHER, thrust, primary gear, front	1	0.114-0.116" (2.89-2.94mm).
	DAM6487	WASHER, thrust, primary gear, front	1	0.116-0.118" (2.94-2.99mm).
	DAM6488	WASHER, thrust, primary gear, front	1	0.118-0.120" (2.99-3.04mm).
	DAM6489	WASHER, thrust, primary gear, front	1	0.120-0.122" (3.04-3.09mm).

Primary Gear Rear Thrust Washers
1959-62, Oil-fed Bush Type 848 Engines
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
27	2A3597	WASHER, thrust, primary gear, rear	1

1961-62, Oil-fed Bush Type 997 Engines
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
28	12A382	WASHER, thrust, primary gear, rear	1
29	12A383	RING, backing	1

1962-63, Deva Bush 848 Engines With 1 3/8" dia. Flywheel Machining.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
30	2A3597	WASHER, thrust, primary gear, rear	1
31	22A449	RING, backing	1

1962 On, Deva Bush 970, 997, 998, 1098, 1070 and 1275 Engines With 1 3/8" or 1 1/2" dia. Flywheel Machining
1963 On, Deva Bush 848 Engines With 1 1/2" dia. Flywheel Machining
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
32	22A319	WASHER, thrust, primary gear, rear	1
33	88G549	RING, backing	1

Idler Gears
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
34	22A304	IDLER GEAR, 31 teeth, 3/4" shaft dia.	1	1959-68; 3 synchro.
	22G943	IDLER GEAR, 31 teeth, 3/4" shaft dia.	1	1968-79; 4 synchro.
	TUB101310	IDLER GEAR, 37 teeth, 7/8" shaft dia.	1	1979 on; 4 synchro, A Plus.
The 3 synchro 22A304 idler gear may be replaced by the equivalent gear from the 4 synchro gearbox, 22G943, so long as the original circlip retaining the idler gear bearing in the gearbox case is replaced with a 22G1141 circlip.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
35	22A1545	WASHER, thrust, 0.130-0.131" (3.30-3.32mm)	2	1959-79; 3 synchro and 4 synchro.
	22A1546	WASHER, thrust, 0.132-0.133" (3.35-3.37mm)	2	1959-79; 3 synchro and 4 synchro.
	22A1547	WASHER, thrust, 0.134-0.135" (3.40-3.42mm)	2	1959-79; 3 synchro and 4 synchro.
	22A1548	WASHER, thrust, 0.136-0.137" (3.45-3.47mm)	2	1959-79; 3 synchro and 4 synchro.
	22A1549	WASHER, thrust, 0.138-0.139" (3.50-3.53mm)	2	1959-79; 3 synchro and 4 synchro.
	DAM5914	WASHER, thrust, 0.130-0.131" (3.30-3.32mm)	2	1979 on; 4 synchro, A Plus.
	DAM4822	WASHER, thrust, 0.132-0.133" (3.35-3.37mm)	2	1979 on; 4 synchro, A Plus.
	DAM4823	WASHER, thrust, 0.134-0.135" (3.40-3.42mm)	2	1979 on; 4 synchro, A Plus.
	DAM4824	WASHER, thrust, 0.136-0.137" (3.45-3.47mm)	2	1979 on; 4 synchro, A Plus.
	DAM4825	WASHER, thrust, 0.138-0.139" (3.50-3.53mm)	2	1979 on; 4 synchro, A Plus.

1st Motion Shaft Drive Gears
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
36	2A3545	DRIVE GEAR, 1st motion shaft, 24 teeth	1	1959-68; 3 synchro.
	22G849	DRIVE GEAR, 1st motion shaft, 24 teeth	1	1968-79; 4 synchro.
	DAM2925	DRIVE GEAR, 1st motion shaft, 29 teeth	1	1979 on; A Plus. Not 1275 (France), 1990-96.
	DAM6337	DRIVE GEAR, 1st motion shaft, 28 teeth	1	A Plus. 1275 (France), 1990-96.
The 3 synchro 2A3548 drive gear may be replaced by the 22G849 gear from the 4 synchro gearbox, so long as distance piece C-STR239 is also used.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
37	2A3548	NUT, drive gear to 1st motion shaft	1
38	DAM4000	LOCK TAB	1

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Manual gearbox - primary, idler and 1st motion shaft drive gears

PRIMARY GEAR-24 TEETH-OIL FED-997cc-'61-'62

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