INTERNAL GEARBOX - 1275CC (1966-74) - Your Shop for British Classic

CAR-IDENTIFICATION LATE SPRITE & MIDGET (1967-1979)

A model year does not necessarily coincide with the year in which the car was built. For example, it may be seen from the following chart that while a car built in January 1972 is indeed a 1972 model year car, another one built in August of that year is a 1973 model year car. There are several different reasons for this. One reason is that it is easier to bring in changes in a model's specification when production has been halted already for a holiday shut down. Another reason is that motor shows usually took place in the Autumn and Winter, displaying the following year's new or updated models. Detailed here are the Sprite and Midget model years relevant to our categories.

Model	Model Year	First chassis no.	Start Date
MG Midget MkIII	1967	G-AN4-52390	October 1966
Austin Healey Sprite MkIV	1967	H-AN9-64735	October 1966

MG Midget MkIII	1968	G-AN4-60460	November 1967
Austin Healey Sprite MkIV	1968	H-AN9-72041	November 1967

MG Midget MkIII	1969	G-AN4-66226	December 1968
Austin Healey Sprite MkIV	1969	H-AN9-77591	December 1968

MG Midget MkIII	1970	G-AN5-74886	September 1969
Austin Healey Sprite MkIV	1970	H-AN10-85287	September 1969

MG Midget MkIII	1971	G-AN5-96273	December 1970
Austin Healey Sprite MkIV	1971	H-AN10-86766	December 1970
Austin Sprite MkIV	1971	A-AN10-86803	January 1971

MG Midget MkIII	1972	G-AN5-105501	October 1971
MG Midget MkIII	1972	G-AN5-123731	July 1972

MG Midget MkIII	1974	G-AN5-138801	August 1973

MG Midget 1500cc	1975	G-AN6-154101	September 1974
MG Midget 1500cc	1976	G-AN6-166301	October 1975
MG Midget 1500cc	1977	G-AN6-182001	August 1976
MG Midget 1500cc	1978	G-AN6-200001	August 1977
MG Midget 1500cc	1979	G-AN6-212001	May 1978
MG Midget 1500cc	1980	G-AN6-229001	October 1979

Serial Number Prefixes

Chassis-numbers
Midget chassis numbers:	G-AN4	(1967 - 1969)
	G-AN5	(1970 - 1974)
	G-AN6	(1975 - 1979)

Sprite chassis numbers:	H-AN9	(1967 - 1969)
	H-AN10	(1970)
	A-AN10	(1971)

Engine numbers
1275cc engine numbers:	12CC/Da/H	(1967)
	12CE/Da/H	(1968 - 1971)
	12V586F	(1972)
	12V588F	(1973)
	12V778F	(1974)

1500cc Engine numbers:	FP	(1975 - 1979)

Body numbers
Midget body numbers:	GBE	(throughout)

Sprite body numbers:	ABL	(throughout)

Where do I find these Numbers?

Chassis Number (All Models)

The chassis number is stamped on a plate secured to the
support step on the LH inner wheel arch under the bonnet.

Body Number (All Models)

The Body Number is stamped on a plate secured to the
LH front door pillar.

Engine Number (1275cc)

The Engine Number is stamped on a plate that is secured
to the RH side of the cylinder block.

Engine Number (1500cc)

The Engine Number is stamped on a flange on the LH
side of the cylinder block.

INTERNAL GEARBOX - 1275CC (1966-74)

Internal Gearbox 1275cc (G-AN4, G-AN5, H-AN9, H-AN10, A-AN10)

The components listed below are those fitted to all original 1275cc Sprite & Midget gearboxes, which used what were termed ‘B’ type gears. However, a number of different gearboxes and sets of internal components have been offered as replacements over the years. Please read the info note below before ordering parts.

So which Gearbox is Fitted to Your Car?

You definitely won’t, of course, find a Mini transverse unit, and it is most unlikely that any one would have fitted a smooth case gearbox: there are too many modifications required to fit what is essentially an inferior gearbox to the 1275cc engine. Plus, ‘spare’ smooth case gearboxes have been thin on the ground for many years. Therefore, you will have a ribbed case gearbox, with one of three distinct gear sets in it :

1. Minor/A35 van/A40 MkII ratios.

2. Sprite/Midget ‘A’ Type gears.

3. Sprite/Midget ‘B’ Type gears.

The principal way to ascertain which of the three you have is to open the gearbox and look at the laygear, which is only just visible behind the mainshaft gear cluster. Normally the part number is stamped on the waist between the largest and second largest gears: 22G83 for a Minor gear set, 22G76 for an ‘A’ Type Sprite/Midget gear set and either 22G232 or (more likely) 22G1100 for a ‘B’ Type Sprite/Midget gear set. To further confirm whether you have a Minor or Sprite/Midget gear set, count the number of teeth on either first, second or third gear, plus the number of teeth on the corresponding cog on the laygear. Divide the former number by the latter and you will have the ratio of that gear.

Ill.no.	Partno.	Part	Quantity required	Info	Price
1	22G229	1ST MOTION INPUT SHAFT	1		CHF 257.90

Ill.no.	Partno.	Part	Quantity required	Info	Price
2	2K6677	LOCK LOCKING, MAINSHAFT	1		CHF 2.55

Ill.no.	Partno.	Part	Quantity required	Info	Price
3	2A3035	LOCKTAB GEARBOX MAINSHAFT	1		CHF 12.30

Ill.no.	Partno.	Part	Quantity required	Info	Price
4	6K559	WASHER PLAIN	1	if fitted	availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Price
5	2K8737	SHIM 0.004"	CHF 5.60
5	2K8738	SHIM 0.006"	CHF 4.90
5	2K8739	SHIM 0.010"	CHF 5.90

Ill.no.	Partno.	Part	Quantity required	Info	Price
6	2A3245	BEARING INPUT SHAFT	1		CHF 24.20

Ill.no.	Partno.	Part	Quantity required	Info	Price
7	6K558	CIRCLIP	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
8	CHM172	BEARING 1ST/3RD MOTION SHAFT 14MM	1		CHF 21.40

Ill.no.	Partno.	Part	Quantity required	Info	Price
10	22G146	MAINSHAFT, 3RD MOTION SHAFT	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
11	22A495	PEG	3		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
12	22G154	SPRING GEARBOX PEG S&M 1098/1275 AND MINI 4SYNCHRO * NL	2		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
14	AEG3009	3RD & 4TH HUB S&M SYNCHRO ASSEMBLY	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
14a	22G95	USE AEG3009OUT	1
14a	AEG3009OUT	3/4 OUTER GEAR	1		CHF 206.25

Ill.no.	Partno.	Part	Quantity required	Info	Price
15	BLS107	BALLBEARING 7/32 DIA	3		CHF 0.60

Ill.no.	Partno.	Part	Quantity required	Info	Price
16	22G317	SPRING SYNCHRONISER	3		CHF 1.55

Ill.no.	Partno.	Part	Quantity required	Info	Price
17	22G2033	SYNCHRO RING	3	3rd/4th & 2nd speed	CHF 48.10

Ill.no.	Partno.	Part	Quantity required	Info	Price
20	22G185	COLLAR LOCKING	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
21	22G1121	GEAR, 3RD SPEED	1		CHF 209.90

Ill.no.	Partno.	Part	Quantity required	Info	Price
22	22G1120	GEAR, 2ND SPEED	1		CHF 192.55

Ill.no.	Partno.	Part	Quantity required	Info	Price
23	22G149	BEARING, 26 PER GEAR	52		CHF 1.10

Ill.no.	Partno.	Part	Quantity required	Info	Price
24	22G156	COLLAR LOCKING	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
25	22G157	WASHER HALF MOON	2		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
26	22G1118	GEAR 1 ST SPEED WITH 2ND SPEED SYNCHRO	1	with 2nd speed synchro	CHF 243.95

Ill.no.	Partno.	Part	Quantity required	Info	Price
27	22G1119	OUTER RING 1ST GEAR	1		CHF 140.80

Ill.no.	Partno.	Part	Quantity required	Info	Price
28	BLS107	BALLBEARING 7/32 DIA	3		CHF 0.60

Ill.no.	Partno.	Part	Quantity required	Info	Price
29	22G317	SPRING SYNCHRONISER	3		CHF 1.55

Ill.no.	Partno.	Part	Quantity required	Info	Price
30	22G89	PLUNGER	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
35	22A463	HOUSING	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
36	22A465	BEARING MAINSHAFT	1		CHF 32.00

Ill.no.	Partno.	Part	Quantity required	Info	Price
37	1G3530	PEG	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
38	6K558	CIRCLIP	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Price
39	2K8737	SHIM 0.004"	CHF 5.60
39	2K8738	SHIM 0.006"	CHF 4.90
39	2K8739	SHIM 0.010"	CHF 5.90

Ill.no.	Partno.	Part	Quantity required	Info	Price
40	22A466	DISTANCE TUBE	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
41	2A3371	SPEEDO DRIVE GEAR	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
42	6K559	WASHER PLAIN	1	If fitted	availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
43	2K6677	LOCK LOCKING, MAINSHAFT	1		CHF 2.55

Ill.no.	Partno.	Part	Quantity required	Info	Price
44	2A3035	LOCKTAB GEARBOX MAINSHAFT	1		CHF 12.30

Ill.no.	Partno.	Part	Quantity required	Info	Price
50	22G1100	LAYGEAR 1275	1		CHF 217.35

Ill.no.	Partno.	Part	Quantity required	Info	Price
51	22G673	LAYSHAFT A-SERIES 948-1275	1		CHF 46.50

Ill.no.	Partno.	Part	Quantity required	Info	Price
52	88G396	CAGED BRG L/GEAR S&M	2		CHF 12.95

Ill.no.	Partno.	Part	Quantity required	Info	Price
53	22G277	DIST PIECE-LAYGEAR(22G1100)	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
54	22G278	SPRING RING L/SHAFT	2		CHF 1.65

Ill.no.	Partno.	Part	Quantity required	Info	Price
55	2A3023	THRUST WASHER LAYGEAR FRONT, 0.125"	1		CHF 27.80

Ill.no.	Partno.	Part	Quantity required	Info	Price
56	2A3024	THRUST WASHER, REAR, +0.123-0.124"	1	alternatives	CHF 27.80
56	2A3025	THRUST WASHER, REAR, +0.125-0.126"	1	alternatives	CHF 27.80
56	2A3026	THRUST WASHER, REAR, +0.127-0.128"	1	alternatives	CHF 27.80
56	2A3027	THRUST WASHER, REAR, +0.130-0.131"	1	alternatives	CHF 27.80

Ill.no.	Partno.	Part	Quantity required	Info	Price
60	22G1114	GEAR REVERSE	1		CHF 112.30

Ill.no.	Partno.	Part	Quantity required	Info	Price
61	2A3282	BUSH REVERSE IDLER GEAR	1		CHF 6.00

Ill.no.	Partno.	Part	Quantity required	Info	Price
62	88G216	REVERSE GEAR SHAFT	1		availability request (add quantity to basket, offer follows)

Ill.no.	Partno.	Part	Quantity required	Info	Price
Internal Gearbox 1275cc (G-AN4, G-AN5, H-AN9, H-AN10, A-AN10) The components listed below are those fitted to all original 1275cc Sprite & Midget gearboxes, which used what were termed ‘B’ type gears. However, a number of different gearboxes and sets of internal components have been offered as replacements over the years. Please read the info note below before ordering parts.
So which Gearbox is Fitted to Your Car? You definitely won’t, of course, find a Mini transverse unit, and it is most unlikely that any one would have fitted a smooth case gearbox: there are too many modifications required to fit what is essentially an inferior gearbox to the 1275cc engine. Plus, ‘spare’ smooth case gearboxes have been thin on the ground for many years. Therefore, you will have a ribbed case gearbox, with one of three distinct gear sets in it : 1. Minor/A35 van/A40 MkII ratios. 2. Sprite/Midget ‘A’ Type gears. 3. Sprite/Midget ‘B’ Type gears. The principal way to ascertain which of the three you have is to open the gearbox and look at the laygear, which is only just visible behind the mainshaft gear cluster. Normally the part number is stamped on the waist between the largest and second largest gears: 22G83 for a Minor gear set, 22G76 for an ‘A’ Type Sprite/Midget gear set and either 22G232 or (more likely) 22G1100 for a ‘B’ Type Sprite/Midget gear set. To further confirm whether you have a Minor or Sprite/Midget gear set, count the number of teeth on either first, second or third gear, plus the number of teeth on the corresponding cog on the laygear. Divide the former number by the latter and you will have the ratio of that gear.
1	22G229	1ST MOTION INPUT SHAFT	1		CHF 257.90
2	2K6677	LOCK LOCKING, MAINSHAFT	1		CHF 2.55
3	2A3035	LOCKTAB GEARBOX MAINSHAFT	1		CHF 12.30
4	6K559	WASHER PLAIN	1	if fitted	availability request (add quantity to basket, offer follows)
5	2K8737	SHIM 0.004"			CHF 5.60
5	2K8738	SHIM 0.006"			CHF 4.90
5	2K8739	SHIM 0.010"			CHF 5.90
6	2A3245	BEARING INPUT SHAFT	1		CHF 24.20
7	6K558	CIRCLIP	1		availability request (add quantity to basket, offer follows)
8	CHM172	BEARING 1ST/3RD MOTION SHAFT 14MM	1		CHF 21.40
10	22G146	MAINSHAFT, 3RD MOTION SHAFT	1		availability request (add quantity to basket, offer follows)
11	22A495	PEG	3		availability request (add quantity to basket, offer follows)
12	22G154	SPRING GEARBOX PEG S&M 1098/1275 AND MINI 4SYNCHRO * NL	2		availability request (add quantity to basket, offer follows)
14	AEG3009	3RD & 4TH HUB S&M SYNCHRO ASSEMBLY	1		availability request (add quantity to basket, offer follows)
14a	22G95	USE AEG3009OUT	1
14a	AEG3009OUT	3/4 OUTER GEAR	1		CHF 206.25
15	BLS107	BALLBEARING 7/32 DIA	3		CHF 0.60
16	22G317	SPRING SYNCHRONISER	3		CHF 1.55
17	22G2033	SYNCHRO RING	3	3rd/4th & 2nd speed	CHF 48.10
20	22G185	COLLAR LOCKING	1		availability request (add quantity to basket, offer follows)
21	22G1121	GEAR, 3RD SPEED	1		CHF 209.90
22	22G1120	GEAR, 2ND SPEED	1		CHF 192.55
23	22G149	BEARING, 26 PER GEAR	52		CHF 1.10
24	22G156	COLLAR LOCKING	1		availability request (add quantity to basket, offer follows)
25	22G157	WASHER HALF MOON	2		availability request (add quantity to basket, offer follows)
26	22G1118	GEAR 1 ST SPEED WITH 2ND SPEED SYNCHRO	1	with 2nd speed synchro	CHF 243.95
27	22G1119	OUTER RING 1ST GEAR	1		CHF 140.80
28	BLS107	BALLBEARING 7/32 DIA	3		CHF 0.60
29	22G317	SPRING SYNCHRONISER	3		CHF 1.55
30	22G89	PLUNGER	1		availability request (add quantity to basket, offer follows)
35	22A463	HOUSING	1		availability request (add quantity to basket, offer follows)
36	22A465	BEARING MAINSHAFT	1		CHF 32.00
37	1G3530	PEG	1		availability request (add quantity to basket, offer follows)
38	6K558	CIRCLIP	1		availability request (add quantity to basket, offer follows)
39	2K8737	SHIM 0.004"			CHF 5.60
39	2K8738	SHIM 0.006"			CHF 4.90
39	2K8739	SHIM 0.010"			CHF 5.90
40	22A466	DISTANCE TUBE	1		availability request (add quantity to basket, offer follows)
41	2A3371	SPEEDO DRIVE GEAR	1		availability request (add quantity to basket, offer follows)
42	6K559	WASHER PLAIN	1	If fitted	availability request (add quantity to basket, offer follows)
43	2K6677	LOCK LOCKING, MAINSHAFT	1		CHF 2.55
44	2A3035	LOCKTAB GEARBOX MAINSHAFT	1		CHF 12.30
50	22G1100	LAYGEAR 1275	1		CHF 217.35
51	22G673	LAYSHAFT A-SERIES 948-1275	1		CHF 46.50
52	88G396	CAGED BRG L/GEAR S&M	2		CHF 12.95
53	22G277	DIST PIECE-LAYGEAR(22G1100)	1		availability request (add quantity to basket, offer follows)
54	22G278	SPRING RING L/SHAFT	2		CHF 1.65
55	2A3023	THRUST WASHER LAYGEAR FRONT, 0.125"	1		CHF 27.80
56	2A3024	THRUST WASHER, REAR, +0.123-0.124"	1	alternatives	CHF 27.80
56	2A3025	THRUST WASHER, REAR, +0.125-0.126"	1	alternatives	CHF 27.80
56	2A3026	THRUST WASHER, REAR, +0.127-0.128"	1	alternatives	CHF 27.80
56	2A3027	THRUST WASHER, REAR, +0.130-0.131"	1	alternatives	CHF 27.80
60	22G1114	GEAR REVERSE	1		CHF 112.30
61	2A3282	BUSH REVERSE IDLER GEAR	1		CHF 6.00
62	88G216	REVERSE GEAR SHAFT	1		availability request (add quantity to basket, offer follows)